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Update v8.19.13

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This section lists all updates associated with version 8.19.13 of the Fleet integration Prebuilt Security Detection Rules.

Rule Description Status Version

Suricata and Elastic Defend Network Correlation

This detection correlates Suricata alerts with Elastic Defend network events to identify the source process performing the network activity.

new

1

Processes with Trailing Spaces

Identify instances where adversaries include trailing space characters to mimic regular files, disguising their activity to evade default file handling mechanisms.

new

5

Ollama API Accessed from External Network

Detects when the Ollama LLM server accepts connections from external IP addresses. Ollama lacks built-in authentication, so exposed instances allow unauthenticated model theft, prompt injection, and resource hijacking.

new

1

Suspected Lateral Movement from Compromised Host

Detects potential lateral movement or post-compromise activity by correlating alerts where the host.ip of one alert matches the source.ip of a subsequent alert. This behavior may indicate a compromised host being used to authenticate to another system or resource, including cloud services.

new

2

Multiple Elastic Defend Alerts from a Single Process Tree

Detects multiple Elastic Defend EDR alerts originating from the same process tree, indicating coordinated malicious activity. Analysts can use this to prioritize triage and response, as these hosts are more likely to be compromised.

new

2

Alerts From Multiple Integrations by Destination Address

This rule uses alert data to determine when multiple alerts from different integrations with unique event categories and involving the same destination.ip are triggered. Analysts can use this to prioritize triage and response, as these IP address is more likely to be related to a compromise.

new

2

Alerts From Multiple Integrations by Source Address

This rule uses alert data to determine when multiple alerts from different integrations with unique event categories and involving the same source.ip are triggered. Analysts can use this to prioritize triage and response, as these IP addresses are more likely to be related to a compromise.

new

2

Alerts From Multiple Integrations by User Name

This rule uses alert data to determine when multiple alerts from different integrations with unique event categories and involving the same user.name are triggered. Analysts can use this to prioritize triage and response, as these users are more likely to be compromised.

new

2

Multiple Alerts in Same ATT&CK Tactic by Host

This rule correlates multiple security alerts associated with the same ATT&CK tactic on a single host within a defined time window. By requiring alerts from multiple distinct detection rules, this detection helps identify hosts exhibiting concentrated malicious behavior, which may indicate an active intrusion or post-compromise activity. The rule is intended to assist analysts in prioritizing triage toward hosts with higher likelihood of compromise rather than signaling a single discrete event.

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2

Multiple External EDR Alerts by Host

This rule uses alert data to determine when multiple external EDR alerts involving the same host are triggered. Analysts can use this to prioritize triage and response, as these hosts are more likely to be compromised.

new

2

Newly Observed Elastic Defend Behavior Alert

This rule detects Elastic Defend behavior alerts that are observed for the first time today when compared against the previous 5 days of alert history. It highlights low-volume, newly observed alerts tied to a specific detection rule, analysts can use this to prioritize triage and response.

new

2

Newly Observed High Severity Detection Alert

This rule detects Elastic SIEM high severity detection alerts that are observed for the first time in the previous 5 days of alert history. It highlights low-volume, newly observed alerts tied to a specific detection rule, analysts can use this to prioritize triage and response.

new

2

Trap Signals Execution

Identify activity related where adversaries can include a trap command which then allows programs and shells to specify commands that will be executed upon receiving interrupt signals.

new

5

Entra ID OAuth Authorization Code Grant for Unusual User, App, and Resource

Identifies the first occurrence of an OAuth 2.0 authorization code grant flow for a specific combination of client application, target resource, and user principal in Microsoft Entra ID. Developer tools like Azure CLI, Visual Studio Code, and Azure PowerShell accessing Microsoft Graph or legacy Azure AD are flagged for infrequent or first time usage by a user. Additionally, any FOCI (Family of Client IDs) application accessing the deprecated Windows Azure Active Directory for the first time is flagged since this resource is rarely accessed legitimately. This pattern is indicative of OAuth phishing attacks like ConsentFix, where attackers steal authorization codes and exchange them for tokens from attacker controlled infrastructure.

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1

GitHub Secret Scanning Disabled

Detects when GitHub Secret Scanning is disabled for a repository. Adversaries may disable secret scanning to evade detection of hardcoded secrets, such as API keys or credentials, that could be used for further compromise or data exfiltration.

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1

GitHub Private Repository Turned Public

Detects when a private GitHub repository is changed to public visibility. Adversaries may change repository visibility to public in order to exfiltrate sensitive code or data, potentially indicating a compromise or unauthorized access.

new

1

GitHub Exfiltration via High Number of Repository Clones by User

Detects a high number of repository cloning actions by a single user within a short time frame. Adversaries may clone multiple repositories to exfiltrate sensitive data.

new

2

Github Activity on a Private Repository from an Unusual IP

Detects when there is activity on a private GitHub repository from an unusual IP address. Adversaries may access private repositories from unfamiliar IPs to exfiltrate sensitive code or data, potentially indicating a compromise or unauthorized access.

new

1

High Number of Closed Pull Requests by User

Detects a high number of closed pull requests by a single user within a short time frame. Adversaries may close multiple pull requests to disrupt development workflows or hide malicious changes.

new

2

Several Failed Protected Branch Force Pushes by User

Detects a high number of failed force push attempts to protected branches by a single user within a short time frame. Adversaries may attempt multiple force pushes to overwrite commit history on protected branches, potentially leading to data loss or disruption of development workflows.

new

2

High Number of Protected Branch Force Pushes by User

Detects a high number of force push actions to protected branches by a single user within a short time frame. Adversaries may perform force pushes to overwrite commit history on protected branches, potentially leading to data loss or disruption of development workflows.

new

2

GitHub Actions Unusual Bot Push to Repository

Detects when the github-actions[bot] pushes code to a repository where it has not performed this behavior before in a certain time window. This may indicate a supply chain attack where malicious code running in a CI workflow attempts to modify repository contents, such as injecting backdoor workflow files.

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1

GitHub Actions Workflow Modification Blocked

Detects when a GitHub Actions workflow attempts to create or modify workflow files in a protected branch but is blocked due to insufficient permissions. This behavior is indicative of a supply chain attack where a malicious package or compromised CI/CD pipeline attempts to inject persistent backdoor workflows into a repository.

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5

New GitHub Personal Access Token (PAT) Added

Detects when a new GitHub Personal Access Token (PAT) is created. Adversaries may create new PATs to maintain persistent access to a compromised account or to escalate privileges within an organization.

new

1

Linux Audio Recording Activity Detected

This rule monitors for the usage of the most common audio recording utilities on unix systems by an uncommon process parent. Adversaries may collect audio data from users or systems for a variety of reasons including espionage, credential theft, or reconnaissance.

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1

Linux Video Recording or Screenshot Activity Detected

This rule monitors for the usage of the most common video recording or screenshot utilities on unix systems by an uncommon process parent. Adversaries may collect video or screenshot data from users or systems for a variety of reasons including espionage, credential theft, or reconnaissance.

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1

Potential Linux Tunneling and/or Port Forwarding via Command Line

This rule monitors for potential tunneling and/or port forwarding activity on Linux systems via command line utilities. Attackers may use various tools to create covert communication channels, allowing them to bypass network security measures and maintain persistent access to compromised systems. By leveraging these utilities, attackers can tunnel traffic through legitimate protocols, making detection more challenging.

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1

Potential Password Spraying Attack via SSH

This rule detects potential password spraying attacks via SSH by identifying multiple failed login attempts from a single source IP address targeting various user accounts within a short time frame. Password spraying is a technique where an attacker attempts to gain unauthorized access by trying a few commonly used passwords against many different accounts, rather than targeting a single account with multiple password attempts.

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2

Linux User or Group Deletion

This rule detects the deletion of user or group accounts on Linux systems. Adversaries may use these commands to remove accounts to cover their tracks or disrupt operations.

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1

System Information Discovery via dmidecode from Parent Shell

This rule detects the use of dmidecode to gather system information from a Linux host when executed from a parent shell process. Adversaries may use dmidecode to collect detailed hardware and system information, which can aid in further exploitation or lateral movement within a network, or be used as a fingerprint for a compromised system.

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1

Potential Data Exfiltration Through Wget

Detects the use of wget to upload files to an internet server. Threat actors often will collect data on a system and attempt to exfiltrate it back to their command and control servers. Use of wget in this way, while not inherently malicious, should be considered highly abnormal and suspicious activity.

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1

React2Shell Network Security Alert

This rule identifies network security alerts related to CVE-2025-55182 exploitation attempts from different network security integrations. CVE-2025-55182 is a critical remote code execution vulnerability in React Server Components (RSC) Flight protocol. The vulnerability allows attackers to execute arbitrary code on the server by sending specially crafted deserialization payloads that exploit prototype chain traversal to access the Function constructor.

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1

Potential Persistence via Mandatory User Profile

Detects the creation or modification of a mandatory user profile hive (NTUSER.MAN) by an unusual process. Adversaries may abuse Windows mandatory profiles by dropping a malicious NTUSER.MAN file containing pre-populated persistence-related registry keys. On the next user logon, Windows loads the registry hive from NTUSER.MAN, causing embedded persistence mechanisms to activate without directly modifying the live registry. This technique can evade traditional registry-based monitoring and indicate a stealthy persistence attempt.

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1

Curl or Wget Spawned via Node.js

This rule detects when Node.js, directly or via a shell, spawns the curl or wget command. This may indicate command and control behavior. Adversaries may use Node.js to download additional tools or payloads onto the system.

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4

GenAI Process Connection to Unusual Domain

Detects GenAI tools connecting to unusual domains on macOS. Adversaries may compromise GenAI tools through prompt injection, malicious MCP servers, or poisoned plugins to establish C2 channels or exfiltrate sensitive data to attacker-controlled infrastructure. AI agents with network access can be manipulated to beacon to external servers, download malicious payloads, or transmit harvested credentials and documents.

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2

Deprecated - Potential Non-Standard Port SSH connection

Identifies potentially malicious processes communicating via a port paring typically not associated with SSH. For example, SSH over port 2200 or port 2222 as opposed to the traditional port 22. Adversaries may make changes to the standard port a protocol uses to bypass filtering or muddle analysis/parsing of network data.

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10

GenAI Process Accessing Sensitive Files

Detects when GenAI tools access sensitive files such as cloud credentials, SSH keys, browser password databases, or shell configurations. Attackers leverage GenAI agents to systematically locate and exfiltrate credentials, API keys, and tokens. Access to credential stores (.aws/credentials, .ssh/id_*) suggests harvesting, while writes to shell configs (.bashrc, .zshrc) indicate persistence attempts. Note: On linux only creation events are available. Access events are not yet implemented.

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2

Multiple Cloud Secrets Accessed by Source Address

This rule detects authenticated sessions accessing secret stores across multiple cloud providers from the same source address within a short period of time. Adversaries with access to compromised credentials or session tokens may attempt to retrieve secrets from services such as AWS Secrets Manager, Google Secret Manager, or Azure Key Vault in rapid succession to expand their access or exfiltrate sensitive information.

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3

Deprecated - Agent Spoofing - Mismatched Agent ID

Detects events that have a mismatch on the expected event agent ID. The status "agent_id_mismatch/mismatch" occurs when the expected agent ID associated with the API key does not match the actual agent ID in an event. This could indicate attempts to spoof events in order to masquerade actual activity to evade detection.

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106

Agent Spoofing - Multiple Hosts Using Same Agent

Detects when multiple hosts are using the same agent ID. This could occur in the event of an agent being taken over and used to inject illegitimate documents into an instance as an attempt to spoof events in order to masquerade actual activity to evade detection.

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106

Tampering of Shell Command-Line History

Adversaries may attempt to clear or disable the Bash command-line history in an attempt to evade detection or forensic investigations.

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111

Unusual Process Modifying GenAI Configuration File

Detects unusual modification of GenAI tool configuration files. Adversaries may inject malicious MCP server configurations to hijack AI agents for persistence, C2, or data exfiltration. Attack vectors include malware or scripts directly poisoning config files, supply chain attacks via compromised dependencies, and prompt injection attacks that abuse the GenAI tool itself to modify its own configuration. Unauthorized MCP servers added to these configs execute arbitrary commands when the AI tool is next invoked.

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2

Masquerading Space After Filename

This rules identifies a process created from an executable with a space appended to the end of the filename. This may indicate an attempt to masquerade a malicious file as benign to gain user execution. When a space is added to the end of certain files, the OS will execute the file according to it’s true filetype instead of it’s extension. Adversaries can hide a program’s true filetype by changing the extension of the file. They can then add a space to the end of the name so that the OS automatically executes the file when it’s double-clicked.

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11

Timestomping using Touch Command

Timestomping is an anti-forensics technique which is used to modify the timestamps of a file, often to mimic files that are in the same folder.

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110

Command Line Obfuscation via Whitespace Padding

Identifies process execution events where the command line value contains a long sequence of whitespace characters or multiple occurrences of contiguous whitespace. Attackers may attempt to evade signature-based detections by padding their malicious command with unnecessary whitespace characters. These observations should be investigated for malicious behavior.

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4

Hosts File Modified

The hosts file on endpoints is used to control manual IP address to hostname resolutions. The hosts file is the first point of lookup for DNS hostname resolution so if adversaries can modify the endpoint hosts file, they can route traffic to malicious infrastructure. This rule detects modifications to the hosts file on Microsoft Windows, Linux (Ubuntu or RHEL) and macOS systems.

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213

M365 or Entra ID Identity Sign-in from a Suspicious Source

This rule correlate Entra-ID or Microsoft 365 mail successful sign-in events with network security alerts by source address. Adversaries may trigger some network security alerts such as reputation or other anomalies before accessing cloud resources.

update

6

Suspicious React Server Child Process

This rule detects suspicious child process activity from a React server application. This could be related to successful exploitation of CVE-2025-55182 or CVE-2025-66478. These vulnerabilities allow attackers to execute remote code due to insecure deserialization of React Server Components (RSC) Flight payloads, leading to unauthenticated RCE on servers running React 19.x or Next.js 14.3.0-canary+, 15.x, and 16.x with the App Router enabled

update

2

Elastic Defend and Network Security Alerts Correlation

This rule correlate any Elastic Defend alert with a set of suspicious events from Network security devices like Palo Alto Networks (PANW) and Fortinet Fortigate by host.ip and source.ip. This may indicate that this host is compromised and triggering multi-datasource alerts.

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4

Elastic Defend and Email Alerts Correlation

This rule correlates any Elastic Defend alert with an email security related alert by target user name. This may indicate the successful execution of a phishing attack.

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3

Multiple Alerts Involving a User

This rule uses alert data to determine when multiple different alerts involving the same user are triggered. Analysts can use this to prioritize triage and response, as these users are more likely to be compromised.

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6

Bash Shell Profile Modification

Both ~/.bash_profile and ~/.bashrc are files containing shell commands that are run when Bash is invoked. These files are executed in a user’s context, either interactively or non-interactively, when a user logs in so that their environment is set correctly. Adversaries may abuse this to establish persistence by executing malicious content triggered by a user’s shell.

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108

SSH Authorized Keys File Activity

The Secure Shell (SSH) authorized_keys file specifies which users are allowed to log into a server using public key authentication. Adversaries may modify it to maintain persistence on a victim host by adding their own public key(s).

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210

SUID/SGID Bit Set

An adversary may add the setuid or setgid bit to a file or directory in order to run a file with the privileges of the owning user or group. An adversary can take advantage of this to either do a shell escape or exploit a vulnerability in an application with the setuid or setgid bit to get code running in a different user’s context. Additionally, adversaries can use this mechanism on their own malware to make sure they’re able to execute in elevated contexts in the future.

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109

Sudoers File Activity

A sudoers file specifies the commands that users or groups can run and from which terminals. Adversaries can take advantage of these configurations to execute commands as other users or spawn processes with higher privileges.

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210

AWS S3 Unauthenticated Bucket Access by Rare Source

Identifies AWS CloudTrail events where an unauthenticated source is attempting to access an S3 bucket. This activity may indicate a misconfigured S3 bucket policy that allows public access to the bucket, potentially exposing sensitive data to unauthorized users. Adversaries can specify --no-sign-request in the AWS CLI to retrieve objects from an S3 bucket without authentication. This is a New Terms rule, which means it will trigger for each unique combination of the source.address and targeted bucket name that has not been seen making this API request.

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6

First Time Seen AWS Secret Value Accessed in Secrets Manager

An adversary with access to a compromised AWS service such as an EC2 instance, Lambda function, or other service may attempt to leverage the compromised service to access secrets in AWS Secrets Manager. This rule looks for the first time a specific user identity has programmatically retrieved a secret value from Secrets Manager using the GetSecretValue action. This rule assumes that AWS services such as Lambda functions and EC2 instances are setup with IAM role’s assigned that have the necessary permissions to access the secrets in Secrets Manager. An adversary with access to a compromised AWS service would rely on its' attached role to access the secrets in Secrets Manager.

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317

AWS Systems Manager SecureString Parameter Request with Decryption Flag

Detects the first occurrence of a user identity accessing AWS Systems Manager (SSM) SecureString parameters using the GetParameter or GetParameters API actions with credentials in the request parameters. This could indicate that the user is accessing sensitive information. This rule detects when a user accesses a SecureString parameter with the withDecryption parameter set to true. This is a New Terms rule that detects the first occurrence of an AWS identity accessing SecureString parameters with decryption.

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7

AWS Config Resource Deletion

Identifies attempts to delete AWS Config resources. AWS Config provides continuous visibility into resource configuration changes and compliance posture across an account. Deleting Config components can significantly reduce security visibility and auditability. Adversaries may delete or disable Config resources to evade detection, hide prior activity, or weaken governance controls before or after other malicious actions.

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212

AWS Configuration Recorder Stopped

Identifies when an AWS Config configuration recorder is stopped. AWS Config recorders continuously track and record configuration changes across supported AWS resources. Stopping the recorder immediately reduces visibility into infrastructure changes and can be abused by adversaries to evade detection, obscure follow-on activity, or weaken compliance and security monitoring controls.

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210

AWS Route 53 Resolver Query Log Configuration Deleted

Identifies the deletion of an Amazon Route 53 Resolver Query Log Configuration. Resolver query logs provide critical visibility into DNS activity across VPCs, including lookups made by EC2 instances, containers, Lambda functions, and other AWS resources. Deleting a query log configuration immediately stops DNS query and response logging for the associated VPC. Adversaries may delete these configurations to evade detection, suppress forensic evidence, or degrade security monitoring capabilities.

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6

AWS SQS Queue Purge

Identifies when an AWS Simple Queue Service (SQS) queue is purged. Purging an SQS queue permanently deletes all messages currently in the queue. Adversaries may use this action to disrupt application workflows, destroy operational data, or impair monitoring and alerting by removing messages that contain evidence of malicious activity.

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5

AWS WAF Access Control List Deletion

Identifies the deletion of an AWS Web Application Firewall (WAF) Web ACL. Web ACLs are the core enforcement objects in AWS WAF, defining which traffic is inspected, allowed, or blocked for protected applications. Deleting a Web ACL removes all associated rules, protections, and logging configurations. Adversaries who obtain sufficient privileges may delete a Web ACL to disable critical security controls, evade detection, or prepare for downstream attacks such as web-application compromise, data theft, or resource abuse. Because Web ACLs are rarely deleted outside of controlled maintenance or infrastructure updates, unexpected deletions may indicate potential defense evasion.

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210

AWS WAF Rule or Rule Group Deletion

Identifies the deletion of an AWS Web Application Firewall (WAF) rule or rule group. WAF rules and rule groups enforce critical protections for web applications by filtering malicious HTTP requests, blocking known attack patterns, and enforcing access controls. Deleting these rules—even briefly—can expose applications to SQL injection, cross-site scripting, credential-stuffing bots, or targeted exploitation. Adversaries who have gained sufficient permissions may remove WAF protections as part of a broader defense evasion or impact strategy, often preceding data theft or direct application compromise.

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210

AWS EC2 User Data Retrieval for EC2 Instance

Identifies discovery request DescribeInstanceAttribute with the attribute userData and instanceId in AWS CloudTrail logs. This may indicate an attempt to retrieve user data from an EC2 instance. Adversaries may use this information to gather sensitive data from the instance such as hardcoded credentials or to identify potential vulnerabilities. This is a New Terms rule that identifies the first time an IAM user or role requests the user data for a specific EC2 instance.

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8

AWS Service Quotas Multi-Region GetServiceQuota Requests

Identifies when a single AWS principal makes GetServiceQuota API calls for the EC2 service quota L-1216C47A, across more than 10 AWS regions within a 30-second window. This quota represents the vCPU limit for on-demand EC2 instances. Adversaries commonly enumerate this quota across regions to assess capacity for large-scale instance deployment, including cryptocurrency mining, malware hosting, or command-and-control infrastructure. This behavior may indicate cloud infrastructure discovery using compromised credentials or a compromised workload.

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7

AWS Lambda Layer Added to Existing Function

Identifies when a Lambda layer is added to an existing AWS Lambda function. Lambda layers allow shared code, dependencies, or runtime modifications to be injected into a function’s execution environment. Adversaries with the ability to update function configurations may add a malicious layer to establish persistence, run unauthorized code, or intercept data handled by the function. This activity should be reviewed to ensure the modification is expected and authorized.

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6

AWS SNS Rare Protocol Subscription by User

Identifies when a use subscribes to an SNS topic using a new protocol type (ie. email, http, lambda, etc.). SNS allows users to subscribe to recieve topic messages across a broad range of protocols like email, sms, lambda functions, http endpoints, and applications. Adversaries may subscribe to an SNS topic to collect sensitive information or exfiltrate data via an external email address, cross-account AWS service or other means. This rule identifies a new protocol subscription method for a particular user.

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7

AWS EventBridge Rule Disabled or Deleted

Identifies when an Amazon EventBridge rule is disabled or deleted. EventBridge rules are commonly used to automate operational workflows and security-relevant routing (for example, forwarding events to Lambda, SNS/SQS, or security tooling). Disabling or deleting a rule can break critical integrations, suppress detections, and reduce visibility. Adversaries may intentionally impair EventBridge rules to disrupt monitoring, delay response, or hide follow-on actions.

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210

AWS EC2 EBS Snapshot Access Removed

Identifies the removal of access permissions from a shared AWS EC2 EBS snapshot. EBS snapshots are essential for data retention and disaster recovery. Adversaries may revoke or modify snapshot permissions to prevent legitimate users from accessing backups, thereby obstructing recovery efforts after data loss or destructive actions. This tactic can also be used to evade detection or maintain exclusive access to critical backups, ultimately increasing the impact of an attack and complicating incident response.

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4

AWS S3 Object Encryption Using External KMS Key

Identifies use of the S3 CopyObject API where the destination object is encrypted using an AWS KMS key from an external AWS account. This behavior may indicate ransomware-style impact activity where an adversary with access to a misconfigured S3 bucket encrypts objects using a KMS key they control, preventing the bucket owner from decrypting their own data. This technique is a critical early signal of destructive intent or cross-account misuse.

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10

AWS S3 Static Site JavaScript File Uploaded

This rule detects when a JavaScript file is uploaded in an S3 static site directory (static/js/) by an IAM user or assumed role. This can indicate suspicious modification of web content hosted on S3, such as injecting malicious scripts into a static website frontend.

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6

Unusual AWS S3 Object Encryption with SSE-C

Identifies when AWS S3 objects stored in a bucket are encrypted using Server-Side Encryption with Customer-Provided Keys (SSE-C). Adversaries with compromised AWS credentials can encrypt objects in an S3 bucket using their own encryption keys, rendering the objects unreadable or recoverable without the key. This can be used as a form of ransomware to extort the bucket owner for the decryption key. This is a New Terms rule that flags when this behavior is observed for the first time user and target bucket name.

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5

AWS CLI with Kali Linux Fingerprint Identified

Identifies usage of the AWS CLI from a client reporting a user agent string indicating the request was made from a Kali Linux distribution. Kali Linux is commonly used for offensive security testing and adversary tradecraft. While not inherently malicious, AWS CLI activity originating from Kali is uncommon in most production environments and may indicate compromised credentials, unauthorized access, or post-exploitation activity using valid cloud accounts.

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3

AWS IAM API Calls via Temporary Session Tokens

Detects sensitive AWS IAM API operations executed using temporary session credentials (access key IDs beginning with "ASIA"). Temporary credentials are commonly issued through sts:GetSessionToken, sts:AssumeRole, or AWS SSO logins and are meant for short-term use. It is unusual for legitimate users or automated processes to perform privileged IAM actions (e.g., creating users, updating policies, or enabling/disabling MFA) with session tokens. This behavior may indicate credential theft, session hijacking, or the abuse of a privileged role’s temporary credentials.

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5

AWS IAM User Created Access Keys For Another User

An adversary with access to a set of compromised credentials may attempt to persist or escalate privileges by creating a new set of credentials for an existing user. This rule looks for use of the IAM CreateAccessKey API operation to create new programmatic access keys for another IAM user.

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11

AWS Lambda Function Policy Updated to Allow Public Invocation

Identifies when an AWS Lambda function policy is updated to allow public invocation. This rule detects use of the AddPermission API where the Principal is set to "*", enabling any AWS account to invoke the function. Adversaries may abuse this configuration to establish persistence, create a covert execution path, or operate a function as an unauthenticated backdoor. Public invocation is rarely required outside very specific workloads and should be considered high-risk when performed unexpectedly.

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5

AWS Route 53 Domain Transfer Lock Disabled

Identifies when the transfer lock on an AWS Route 53 domain is disabled. The transfer lock protects domains from being moved to another registrar or AWS account without authorization. Disabling this lock removes an important safeguard against domain hijacking. Adversaries who gain access to domain-management permissions may disable the lock as a precursor to unauthorized domain transfer, takeover, or service disruption.

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210

AWS Route 53 Domain Transferred to Another Account

Identifies when an AWS Route 53 domain is transferred to another AWS account. Transferring a domain changes administrative control of the DNS namespace, enabling the receiving account to modify DNS records, route traffic, request certificates, and potentially hijack operational workloads. Adversaries who gain access to privileged IAM users or long-lived credentials may leverage domain transfers to establish persistence, redirect traffic, conduct phishing, or stage infrastructure for broader attacks. This rule detects successful domain transfer requests.

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210

AWS Route 53 Private Hosted Zone Associated With a VPC

Identifies when an AWS Route 53 private hosted zone is associated with a new Virtual Private Cloud (VPC). Private hosted zones restrict DNS resolution to specific VPCs, and associating additional VPCs expands the scope of what networks can resolve internal DNS records. Adversaries with sufficient permissions may associate unauthorized VPCs to intercept, observe, or reroute internal traffic, establish persistence, or expand their visibility within an AWS environment.

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210

AWS IAM Customer-Managed Policy Attached to Role by Rare User

Detects when an AWS Identity and Access Management (IAM) customer-managed policy is attached to a role by an unusual or unauthorized user. Customer-managed policies are policies created and controlled within an AWS account, granting specific permissions to roles or users when attached. This rule identifies potential privilege escalation by flagging cases where a customer-managed policy is attached to a role by an unexpected actor, which could signal unauthorized access or misuse. Attackers may attach policies to roles to expand permissions and elevate their privileges within the AWS environment. This is a New Terms rule that uses the "cloud.account.id", "user.name" and "target.entity.id" fields to check if the combination of the actor identity and target role name has not been seen before.

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7

AWS IAM Assume Role Policy Update

Identifies AWS CloudTrail events where an IAM role’s trust policy has been updated by an IAM user or Assumed Role identity. The trust policy is a JSON document that defines which principals are allowed to assume the role. An attacker may attempt to modify this policy to gain the privileges of the role. This is a New Terms rule, which means it will only trigger once for each unique combination of the "cloud.account.id", "user.name" and "target.entity.id" fields, that have not been seen making this API request.

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215

AWS STS Role Assumption by Service

Identifies when a service has assumed a role in AWS Security Token Service (STS). Services can assume a role to obtain temporary credentials and access AWS resources. Adversaries can use this technique for credential access and privilege escalation. This is a New Terms rule that identifies when a service assumes a role in AWS Security Token Service (STS) to obtain temporary credentials and access AWS resources. While often legitimate, adversaries may use this technique for unauthorized access, privilege escalation, or lateral movement within an AWS environment.

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214

AWS STS Role Assumption by User

Identifies when a user or role has assumed a role in AWS Security Token Service (STS). Users can assume a role to obtain temporary credentials and access AWS resources. Adversaries can use this technique for credential access and privilege escalation. This is a New Terms rule that identifies when a service assumes a role in AWS Security Token Service (STS) to obtain temporary credentials and access AWS resources. While often legitimate, adversaries may use this technique for unauthorized access, privilege escalation, or lateral movement within an AWS environment.

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6

Entra ID SharePoint Accessed by Unusual User and Microsoft Authentication Broker Client

This rule detects non-interactive authentication activity against SharePoint Online (Office 365 SharePoint Online) by a user principal via the Microsoft Authentication Broker application. The session leverages a refresh token or Primary Refresh Token (PRT) without interactive sign-in, often used in OAuth phishing or token replay scenarios.

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3

Microsoft Graph Request Email Access by Unusual User and Client

Identifies access to email resources via Microsoft Graph API using an first-party application on behalf of a user principal. This behavior may indicate an adversary using a phished OAuth refresh token or a Primary Refresh Token (PRT) to access email resources. The pattern includes requests to Microsoft Graph API endpoints related to email, such as /me/mailFolders/inbox/messages or /users/{user_id}/messages, using a public client application ID and a user principal object ID. This is a New Terms rule that only signals if the application ID and user principal object ID have not been seen doing this activity in the last 14 days.

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3

Entra ID OAuth Device Code Flow with Concurrent Sign-ins

Identifies concurrent Entra ID sign-in events for the same user and session from multiple sources, and where one of the authentication event has some suspicious properties often associated to DeviceCode and OAuth phishing. Adversaries may steal Refresh Tokens (RTs) via phishing to bypass multi-factor authentication (MFA) and gain unauthorized access to Azure resources.

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3

Entra ID User Sign-in Brute Force Attempted

Identifies potential brute-force attacks targeting user accounts by analyzing failed sign-in patterns in Microsoft Entra ID Sign-In Logs. This detection focuses on a high volume of failed interactive or non-interactive authentication attempts within a short time window, often indicative of password spraying, credential stuffing, or password guessing. Adversaries may use these techniques to gain unauthorized access to applications integrated with Entra ID or to compromise valid user accounts.

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8

Entra ID Sign-in Brute Force Attempted (Microsoft 365)

Identifies potential brute-force attacks targeting Microsoft 365 user accounts by analyzing failed sign-in patterns in Microsoft Entra ID Sign-In Logs. This detection focuses on a high volume of failed interactive or non-interactive authentication attempts within a short time window, often indicative of password spraying, credential stuffing, or password guessing. Adversaries may use these techniques to gain unauthorized access to Microsoft 365 services such as Exchange Online, SharePoint, or Teams.

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110

Entra ID Concurrent Sign-in with Suspicious Properties

Identifies concurrent azure signin events for the same user and from multiple sources, and where one of the authentication event has some suspicious properties often associated to DeviceCode and OAuth phishing. Adversaries may steal Refresh Tokens (RTs) via phishing to bypass multi-factor authentication (MFA) and gain unauthorized access to Azure resources.

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6

Entra ID MFA TOTP Brute Force Attempted

Identifies brute force attempts against Azure Entra multi-factor authentication (MFA) Time-based One-Time Password (TOTP) verification codes. This rule detects high frequency failed TOTP code attempts for a single user in a short time-span with a high number of distinct session IDs. Adversaries may programmatically attemopt to brute-force TOTP codes by generating several sessions and attempt to guess the correct code.

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8

Azure Key Vault Excessive Secret or Key Retrieved

Identifies excessive secret or key retrieval operations from Azure Key Vault. This rule detects when a user principal retrieves secrets or keys from Azure Key Vault multiple times within a short time frame, which may indicate potential abuse or unauthorized access attempts. The rule focuses on high-frequency retrieval operations that deviate from normal user behavior, suggesting possible credential harvesting or misuse of sensitive information.

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7

Azure Key Vault Unusual Secret Key Usage

Identifies secrets, keys, or certificates retrieval operations from Azure Key Vault by a user principal that has not been seen previously doing so in a certain amount of days. Azure Key Vault is a cloud service for securely storing and accessing secrets, keys, and certificates. Unauthorized or excessive retrievals may indicate potential abuse or unauthorized access attempts.

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3

Azure VNet Full Network Packet Capture Enabled

Identifies potential full network packet capture in Azure. Packet Capture is an Azure Network Watcher feature that can be used to inspect network traffic. This feature can potentially be abused to read sensitive data from unencrypted internal traffic.

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108

Azure Event Hub Deleted

Identifies an Event Hub deletion in Azure. An Event Hub is an event processing service that ingests and processes large volumes of events and data. An adversary may delete an Event Hub in an attempt to evade detection.

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107

Azure Diagnostic Settings Deleted

Identifies the deletion of diagnostic settings in Azure, which send platform logs and metrics to different destinations. An adversary may delete diagnostic settings in an attempt to evade defenses.

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108

Azure Kubernetes Services (AKS) Kubernetes Events Deleted

Identifies when events are deleted in Azure Kubernetes. Kubernetes events are objects that log any state changes. Example events are a container creation, an image pull, or a pod scheduling on a node. An adversary may delete events in Azure Kubernetes in an attempt to evade detection.

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107

Azure VNet Firewall Policy Deleted

Identifies the deletion of a firewall policy in Azure. An adversary may delete a firewall policy in an attempt to evade defenses and/or to eliminate barriers to their objective.

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107

Azure VNet Firewall Front Door WAF Policy Deleted

Identifies the deletion of a Frontdoor Web Application Firewall (WAF) Policy in Azure. An adversary may delete a Frontdoor Web Application Firewall (WAF) Policy in an attempt to evade defenses and/or to eliminate barriers to their objective.

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107

Azure VNet Network Watcher Deleted

Identifies the deletion of a Network Watcher in Azure. Network Watchers are used to monitor, diagnose, view metrics, and enable or disable logs for resources in an Azure virtual network. An adversary may delete a Network Watcher in an attempt to evade defenses.

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107

Azure Diagnostic Settings Alert Suppression Rule Created or Modified

Identifies the creation of suppression rules in Azure. Suppression rules are a mechanism used to suppress alerts previously identified as false positives or too noisy to be in production. This mechanism can be abused or mistakenly configured, resulting in defense evasions and loss of security visibility.

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107

Azure Blob Storage Permissions Modified

Identifies when the Azure role-based access control (Azure RBAC) permissions are modified for an Azure Blob. An adversary may modify the permissions on a blob to weaken their target’s security controls or an administrator may inadvertently modify the permissions, which could lead to data exposure or loss.

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109

Entra ID Sign-in BloodHound Suite User-Agent Detected

Identifies potential enumeration activity using AzureHound, SharpHound, or BloodHound across Microsoft cloud services. These tools are often used by red teamers and adversaries to map users, groups, roles, applications, and access relationships within Microsoft Entra ID (Azure AD) and Microsoft 365.

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2

Entra ID Sign-in TeamFiltration User-Agent Detected

Identifies potential enumeration or password spraying activity using TeamFiltration tool. TeamFiltration is an open-source enumeration, password spraying and exfiltration tool designed for Entra ID and Microsoft 365. Adversaries are known to use TeamFiltration in-the-wild to enumerate users, groups, and roles, as well as to perform password spraying attacks against Microsoft Entra ID and Microsoft 365 accounts. This rule detects the use of TeamFiltration by monitoring for specific user-agent strings associated with the tool in Azure and Microsoft 365 logs.

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2

Azure Blob Storage Container Access Level Modified

Identifies changes to container access levels in Azure. Anonymous public read access to containers and blobs in Azure is a way to share data broadly, but can present a security risk if access to sensitive data is not managed judiciously.

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107

Azure Compute VM Command Executed

Identifies command execution on a virtual machine (VM) in Azure. A Virtual Machine Contributor role lets you manage virtual machines, but not access them, nor access the virtual network or storage account they’re connected to. However, commands can be run via PowerShell on the VM, which execute as System. Other roles, such as certain Administrator roles may be able to execute commands on a VM as well.

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107

Azure Kubernetes Services (AKS) Kubernetes Pods Deleted

Identifies the deletion of Azure Kubernetes Pods. Adversaries may delete a Kubernetes pod to disrupt the normal behavior of the environment.

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107

Azure Resource Group Deleted

Identifies the deletion of a resource group in Azure, which includes all resources within the group. Deletion is permanent and irreversible. An adversary may delete a resource group in an attempt to evade defenses or intentionally destroy data.

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107

Entra ID Actor Token User Impersonation Abuse

Identifies potential abuse of actor tokens in Microsoft Entra ID audit logs. Actor tokens are undocumented backend mechanisms used by Microsoft for service-to-service (S2S) operations, allowing services to perform actions on behalf of users. These tokens appear in logs with the service’s display name but the impersonated user’s UPN. While some legitimate Microsoft operations use actor tokens, unexpected usage may indicate exploitation of CVE-2025-55241, which allowed unauthorized access to Azure AD Graph API across tenants before being patched by Microsoft.

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4

Entra ID OAuth Device Code Grant by Microsoft Authentication Broker

Identifies device code authentication with an Azure broker client for Entra ID. Adversaries abuse Primary Refresh Tokens (PRTs) to bypass multi-factor authentication (MFA) and gain unauthorized access to Azure resources. PRTs are used in Conditional Access policies to enforce device-based controls. Compromising PRTs allows attackers to bypass these policies and gain unauthorized access. This rule detects successful sign-ins using device code authentication with the Entra ID broker client application ID (29d9ed98-a469-4536-ade2-f981bc1d605e).

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6

Entra ID External Guest User Invited

Identifies an invitation to an external user in Azure Active Directory (AD). Azure AD is extended to include collaboration, allowing you to invite people from outside your organization to be guest users in your cloud account. Unless there is a business need to provision guest access, it is best practice avoid creating guest users. Guest users could potentially be overlooked indefinitely leading to a potential vulnerability.

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107

Entra ID OAuth Device Code Grant by Unusual User

Identifies when a user is observed for the first time in the last 14 days authenticating using the device code authentication workflow. This authentication workflow can be abused by attackers to phish users and steal access tokens to impersonate the victim. By its very nature, device code should only be used when logging in to devices without keyboards, where it is difficult to enter emails and passwords.

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7

Entra ID OAuth User Impersonation to Microsoft Graph

Identifies potential session hijacking or token replay in Microsoft Entra ID. This rule detects cases where a user signs in and subsequently accesses Microsoft Graph from a different IP address using the same session ID. This may indicate a successful OAuth phishing attack, session hijacking, or token replay attack, where an adversary has stolen a session cookie or refresh/access token and is impersonating the user from an alternate host or location.

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8

Entra ID High Risk Sign-in

Identifies high risk Microsoft Entra ID sign-ins by leveraging Microsoft’s Identity Protection machine learning and heuristics. Identity Protection categorizes risk into three tiers: low, medium, and high. While Microsoft does not provide specific details about how risk is calculated, each level brings higher confidence that the user or sign-in is compromised.

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110

Entra ID Illicit Consent Grant via Registered Application

Identifies an illicit consent grant request on-behalf-of a registered Entra ID application. Adversaries may create and register an application in Microsoft Entra ID for the purpose of requesting user consent to access resources. This is accomplished by tricking a user into granting consent to the application, typically via a pre-made phishing URL. This establishes an OAuth grant that allows the malicious client applocation to access resources on-behalf-of the user.

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219

Entra ID OAuth Phishing via First-Party Microsoft Application

Detects potentially suspicious OAuth authorization activity in Microsoft Entra ID where first-party Microsoft applications from the FOCI (Family of Client IDs) group request access to Microsoft Graph or legacy Azure AD resources. Developer tools like Azure CLI, Visual Studio Code, and Azure PowerShell accessing these resources are flagged, as they are commonly abused in phishing campaigns like ConsentFix. Additionally, any FOCI family application accessing the deprecated Windows Azure Active Directory resource is flagged since this API is rarely used legitimately and attackers target it for stealth. First-party apps are trusted by default in all tenants and cannot be blocked, making them ideal for OAuth phishing attacks.

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5

Entra ID OAuth user_impersonation Scope for Unusual User and Client

Identifies rare occurrences of OAuth workflow for a user principal that is single factor authenticated, with an OAuth scope containing user_impersonation for a token issued by Entra ID. Adversaries may use this scope to gain unauthorized access to user accounts, particularly when the sign-in session status is unbound, indicating that the session is not associated with a specific device or session. This behavior is indicative of potential account compromise or unauthorized access attempts. This rule flags when this pattern is detected for a user principal that has not been seen in the last 10 days, indicating potential abuse or unusual activity.

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4

Entra ID PowerShell Sign-in

Identifies a sign-in using the Azure Active Directory PowerShell module. PowerShell for Azure Active Directory allows for managing settings from the command line, which is intended for users who are members of an admin role.

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109

Entra ID Protection Alerts for User Detected

Identifies more than two Microsoft Entra ID Protection alerts associated to the user principal in a short time period. Microsoft Entra ID Protection alerts are triggered by suspicious sign-in activity, such as anomalous IP addresses, risky sign-ins, or other risk detections. Multiple alerts in a short time frame may indicate an ongoing attack or compromised account.

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3

Entra ID Protection - Risk Detection - Sign-in Risk

Identifies sign-in risk detection events via Microsofts Entra ID Protection service. Entra ID Protection detects sign-in activity such as anonymized IP addresses, unlikely travel, password spray, and more.

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4

Entra ID Protection - Risk Detection - User Risk

Identifies user risk detection events via Microsofts Entra ID Protection service. Entra ID Protection detects user risk activity such as anonymized IP addresses, unlikely travel, password spray, and more.

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3

Entra ID User Sign-in with Unusual Client

Detects rare non-interactive sign-ins where an Entra ID client application authenticates on behalf of a principal user using an application (client) ID that is not commonly associated with that user’s historical sign-in behavior. Adversaries with stolen credentials or OAuth tokens may abuse Entra ID–managed or first-party client IDs to perform on-behalf-of (OBO) authentication, blending into legitimate cloud traffic while avoiding traditional interactive sign-in flows. This technique is commonly observed in OAuth phishing, token theft, and access broker operations, and may precede lateral movement, persistence, or data access via Microsoft Graph or other cloud resources. The rule uses a New Terms approach to identify first-seen combinations of the UPN and Client ID within a defined history window, helping surface unexpected client usage that may indicate compromised identities, malicious automation, or unauthorized application impersonation.

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5

Entra ID User Sign-in with Unusual Authentication Type

Identifies rare instances of authentication requirements for Azure Entra ID principal users. An adversary with stolen credentials may attempt to authenticate with unusual authentication requirements, which is a rare event and may indicate an attempt to bypass conditional access policies (CAP) and multi-factor authentication (MFA) requirements. The authentication requirements specified may not be commonly used by the user based on their historical sign-in activity.

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6

Entra ID High Risk User Sign-in Heuristic

Identifies high risk Azure Active Directory (AD) sign-ins by leveraging Microsoft Identity Protection machine learning and heuristics.

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109

Entra ID OAuth Flow by Microsoft Authentication Broker to Device Registration Service (DRS)

Identifies separate OAuth authorization flows in Microsoft Entra ID where the same user principal and session ID are observed across multiple IP addresses within a 5-minute window. These flows involve the Microsoft Authentication Broker (MAB) as the client application and the Device Registration Service (DRS) as the target resource. This pattern is highly indicative of OAuth phishing activity, where an adversary crafts a legitimate Microsoft login URL to trick a user into completing authentication and sharing the resulting authorization code, which is then exchanged for an access and refresh token by the attacker.

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7

Entra ID OAuth ROPC Grant Login Detected

Detects unusual resource owner password credential (ROPC) login attempts by a user principal in Microsoft Entra ID. ROPC is a legacy authentication flow that allows applications to obtain tokens by directly providing user credentials. This method is less secure and can be exploited by adversaries to gain access to user accounts without requiring multi-factor authentication (MFA), especially during enumeration or password spraying. This is a New Terms rule that identifies when user principals are involved in ROPC login attempts, not seen before in the last 10 days, indicating potential abuse or unusual activity.

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2

Entra ID User Reported Suspicious Activity

Identifies suspicious activity reported by users in Microsoft Entra ID where users have reported suspicious activity related to their accounts, which may indicate potential compromise or unauthorized access attempts. Reported suspicious activity typically occurs during the authentication process and may involve various authentication methods, such as password resets, account recovery, or multi-factor authentication challenges. Adversaries may attempt to exploit user accounts by leveraging social engineering techniques or other methods to gain unauthorized access to sensitive information or resources.

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4

Microsoft Graph Request User Impersonation by Unusual Client

This New Terms rule focuses on the first occurrence of a client application ID (azure.graphactivitylogs.properties.app_id) making a request to Microsoft Graph API for a specific tenant ID (azure.tenant_id) and user principal object ID (azure.graphactivitylogs.properties.user_principal_object_id). This rule may helps identify unauthorized access or actions performed by compromised accounts. Advesaries may succesfully compromise a user’s credentials and use the Microsoft Graph API to access resources or perform actions on behalf of the user.

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5

Entra ID Application Credential Modified

Identifies when a new credential is added to an application in Azure. An application may use a certificate or secret string to prove its identity when requesting a token. Multiple certificates and secrets can be added for an application and an adversary may abuse this by creating an additional authentication method to evade defenses or persist in an environment.

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107

Entra ID Conditional Access Policy (CAP) Modified

Identifies a modification to a conditional access policy (CAP) in Microsoft Entra ID. Adversaries may modify existing CAPs to loosen access controls and maintain persistence in the environment with a compromised identity or entity.

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108

Entra ID OIDC Discovery URL Modified

Detects a change to the OpenID Connect (OIDC) discovery URL in the Entra ID Authentication Methods Policy. This behavior may indicate an attempt to federate Entra ID with an attacker-controlled identity provider, enabling bypass of multi-factor authentication (MFA) and unauthorized access through bring-your-own IdP (BYOIDP) methods.

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7

Entra ID Global Administrator Role Assigned (PIM User)

Identifies an Azure Active Directory (AD) Global Administrator role addition to a Privileged Identity Management (PIM) user account. PIM is a service that enables you to manage, control, and monitor access to important resources in an organization. Users who are assigned to the Global administrator role can read and modify any administrative setting in your Azure AD organization.

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107

Entra ID Privileged Identity Management (PIM) Role Modified

Azure Active Directory (AD) Privileged Identity Management (PIM) is a service that enables you to manage, control, and monitor access to important resources in an organization. PIM can be used to manage the built-in Azure resource roles such as Global Administrator and Application Administrator. An adversary may add a user to a PIM role in order to maintain persistence in their target’s environment or modify a PIM role to weaken their target’s security controls.

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109

Entra ID OAuth PRT Issuance to Non-Managed Device Detected

Identifies when a user signs in with a refresh token using the Microsoft Authentication Broker (MAB) client, followed by a Primary Refresh Token (PRT) sign-in from the same device within 1 hour from an unmanaged device. This pattern may indicate that an attacker has successfully registered a device using ROADtx and transitioned from short-term token access to long-term persistent access via PRTs. Excluding access to the Device Registration Service (DRS) ensures the PRT is being used beyond registration, often to access Microsoft 365 resources like Outlook or SharePoint.

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3

Entra ID Service Principal Created

Identifies when a new service principal is added in Microsoft Entra ID. An application, hosted service, or automated tool that accesses or modifies resources needs an identity created. This identity is known as a service principal. For security reasons, it’s always recommended to use service principals with automated tools rather than allowing them to log in with a user identity.

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109

Entra ID Service Principal Credentials Created by Unusual User

Identifies when new Service Principal credentials have been added in Microsoft Entra ID. In most organizations, credentials will be added to service principals infrequently. Hijacking an application (by adding a rogue secret or certificate) with granted permissions will allow the attacker to access data that is normally protected by MFA requirements.

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108

Entra ID ADRS Token Request by Microsoft Authentication Broker

Detects suspicious OAuth 2.0 token requests where the Microsoft Authentication Broker (29d9ed98-a469-4536-ade2-f981bc1d605e) requests access to the Device Registration Service (01cb2876-7ebd-4aa4-9cc9-d28bd4d359a9) on behalf of a user principal. The presence of the adrs_access scope in the authentication processing details suggests an attempt to access ADRS, which is atypical for standard user sign-ins. This behavior may reflect an effort to abuse device registration for unauthorized persistence, such as acquiring a Primary Refresh Token (PRT) or establishing a trusted session.

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2

Entra ID Device Registration Detected (ROADtools)

Detects a sequence of events in Microsoft Entra ID indicative of a suspicious cloud-based device registration, potentially using ROADtools. This behavior involves adding a device via the Device Registration Service, followed by the assignment of registered users and owners — a pattern consistent with techniques used to establish persistence or acquire a Primary Refresh Token (PRT). ROADtools, a popular red team toolkit, often leaves distinct telemetry signatures such as the Microsoft.OData.Client user agent and specific OS version values. These sequences are uncommon in typical user behavior and may reflect abuse of device trust for session hijacking or silent token replay.

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2

Entra ID User Added as Registered Application Owner

Identifies when a user is added as an owner for an Azure application. An adversary may add a user account as an owner for an Azure application in order to grant additional permissions and modify the application’s configuration using another account.

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107

Entra ID User Added as Service Principal Owner

Identifies when a user is added as an owner for an Azure service principal. The service principal object defines what the application can do in the specific tenant, who can access the application, and what resources the app can access. A service principal object is created when an application is given permission to access resources in a tenant. An adversary may add a user account as an owner for a service principal and use that account in order to define what an application can do in the Azure AD tenant.

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107

Entra ID User Sign-in with Unusual Non-Managed Device

Identifies when a Microsoft Entra ID user signs in from a device that is not typically used by the user and is not managed, which may indicate potential compromise or unauthorized access attempts. This rule detects unusual sign-in activity by comparing the device used for the sign-in against the user’s typical device usage patterns. Adversaries may create and register a new device to obtain a Primary Refresh Token (PRT) and maintain persistent access.

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2

Entra ID External Authentication Methods (EAM) Modified

Identifies when an external authentication method (EAM) is added or modified in Entra ID. EAM may allow adversaries to bypass multi-factor authentication (MFA) requirements, potentially leading to unauthorized access to user accounts and sensitive resources by using bring-your-own IdP (BYOIDP) methods.

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2

Entra ID Protection User Alert and Device Registration

Identifies sequence of events where a Microsoft Entra ID protection alert is followed by an attempt to register a new device by the same user principal. This behavior may indicate an adversary using a compromised account to register a device, potentially leading to unauthorized access to resources or persistence in the environment.

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2

Entra ID Elevated Access to User Access Administrator

Identifies when a user has elevated their access to User Access Administrator for their Azure Resources. The User Access Administrator role allows users to manage user access to Azure resources, including the ability to assign roles and permissions. Adversaries may target an Entra ID Global Administrator or other privileged role to elevate their access to User Access Administrator, which can lead to further privilege escalation and unauthorized access to sensitive resources. This is a New Terms rule that only signals if the user principal name has not been seen doing this activity in the last 14 days.

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3

Azure Kubernetes Services (AKS) Kubernetes Rolebindings Created

Identifies the creation of role binding or cluster role bindings. You can assign these roles to Kubernetes subjects (users, groups, or service accounts) with role bindings and cluster role bindings. An adversary who has permissions to create bindings and cluster-bindings in the cluster can create a binding to the cluster-admin ClusterRole or to other high privileges roles.

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107

New GitHub Self Hosted Action Runner

This rule detects the creation of a self-hosted Github runner from a first time seen user.name in the last 5 days. Adversaries may abuse self-hosted runners to execute workflow jobs on customer infrastructure.

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2

M365 Exchange Mailbox Items Accessed Excessively

Identifies an excessive number of Microsoft 365 mailbox items accessed by a user either via aggregated counts or throttling. Microsoft audits mailbox access via the MailItemsAccessed event, which is triggered when a user accesses mailbox items. If more than 1000 mailbox items are accessed within a 24-hour period, it is then throttled. Excessive mailbox access may indicate an adversary attempting to exfiltrate sensitive information or perform reconnaissance on a target’s mailbox. This rule detects both the throttled and unthrottled events with a high threshold.

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3

M365 Exchange Mailbox Accessed by Unusual Client

Identifies suspicious Microsoft 365 mail access by ClientAppId. This rule detects when a user accesses their mailbox using a client application that is not typically used by the user, which may indicate potential compromise or unauthorized access attempts. Adversaries may use custom or third-party applications to access mailboxes, bypassing standard security controls. First-party Microsoft applications are also abused after OAuth tokens are compromised, allowing adversaries to access mailboxes without raising suspicion.

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112

M365 Exchange Inbox Forwarding Rule Created

Identifies when a new Inbox forwarding rule is created in Microsoft 365. Inbox rules process messages in the Inbox based on conditions and take actions. In this case, the rules will forward the emails to a defined address. Attackers can abuse Inbox Rules to intercept and exfiltrate email data without making organization-wide configuration changes or having the corresponding privileges.

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211

M365 Identity OAuth Flow by User Sign-in to Device Registration

Identifies attempts to register a new device in Microsoft Entra ID after OAuth authentication with authorization code grant. Adversaries may use OAuth phishing techniques to obtain an OAuth authorization code, which can then be exchanged for access and refresh tokens. This rule detects a sequence of events where a user principal authenticates via OAuth, followed by a device registration event, indicating potential misuse of the OAuth flow to establish persistence or access resources.

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3

M365 Identity User Brute Force Attempted

Identifies brute-force authentication activity targeting Microsoft 365 user accounts using failed sign-in patterns that match password spraying, credential stuffing, or password guessing behavior. Adversaries may attempt brute-force authentication with credentials obtained from previous breaches, leaks, marketplaces or guessable passwords.

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417

M365 Identity Excessive SSO Login Errors Reported

Identifies accounts with a high number of single sign-on (SSO) logon errors. Excessive logon errors may indicate an attempt to brute force a password or SSO token.

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212

M365 Identity User Account Lockouts

Detects a burst of Microsoft 365 user account lockouts within a short 5-minute window. A high number of IdsLocked login errors across multiple user accounts may indicate brute-force attempts for the same users resulting in lockouts.

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7

M365 Identity OAuth Flow by First-Party Microsoft App from Multiple IPs

Identifies sign-ins on behalf of a principal user to the Microsoft Graph or legacy Azure AD API from multiple IPs using first-party Microsoft applications from the FOCI (Family of Client IDs) group. Developer tools like Azure CLI, VSCode, and Azure PowerShell accessing these resources from multiple IPs are flagged, along with any FOCI application accessing the deprecated Windows Azure Active Directory from multiple IPs. This behavior may indicate an adversary using a phished OAuth authorization code or refresh token, as seen in attacks like ConsentFix where attackers steal localhost OAuth codes and replay them from attacker infrastructure.

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7

M365 Exchange Anti-Phish Policy Deleted

Identifies the deletion of an anti-phishing policy in Microsoft 365. By default, Microsoft 365 includes built-in features that help protect users from phishing attacks. Anti-phishing polices increase this protection by refining settings to better detect and prevent attacks.

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211

M365 Exchange Anti-Phish Rule Modification

Identifies the modification of an anti-phishing rule in Microsoft 365. By default, Microsoft 365 includes built-in features that help protect users from phishing attacks. Anti-phishing rules increase this protection by refining settings to better detect and prevent attacks.

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211

M365 Exchange DKIM Signing Configuration Disabled

Identifies when a DomainKeys Identified Mail (DKIM) signing configuration is disabled in Microsoft 365. With DKIM in Microsoft 365, messages that are sent from Exchange Online will be cryptographically signed. This will allow the receiving email system to validate that the messages were generated by a server that the organization authorized and were not spoofed.

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211

M365 Exchange DLP Policy Deleted

Identifies when a Data Loss Prevention (DLP) policy is removed in Microsoft 365. An adversary may remove a DLP policy to evade existing DLP monitoring.

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211

M365 Exchange Email Safe Link Policy Disabled

Identifies when a Safe Link policy is disabled in Microsoft 365. Safe Link policies for Office applications extend phishing protection to documents that contain hyperlinks, even after they have been delivered to a user.

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211

M365 Exchange Mailbox Audit Logging Bypass Added

Detects the occurrence of mailbox audit bypass associations. The mailbox audit is responsible for logging specified mailbox events (like accessing a folder or a message or permanently deleting a message). However, actions taken by some authorized accounts, such as accounts used by third-party tools or accounts used for lawful monitoring, can create a large number of mailbox audit log entries and may not be of interest to your organization. Because of this, administrators can create bypass associations, allowing certain accounts to perform their tasks without being logged. Attackers can abuse this allowlist mechanism to conceal actions taken, as the mailbox audit will log no activity done by the account.

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211

M365 Exchange Malware Filter Policy Deleted

Identifies when a malware filter policy has been deleted in Microsoft 365. A malware filter policy is used to alert administrators that an internal user sent a message that contained malware. This may indicate an account or machine compromise that would need to be investigated. Deletion of a malware filter policy may be done to evade detection.

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211

M365 Exchange Malware Filter Rule Modified

Identifies when a malware filter rule has been deleted or disabled in Microsoft 365. An adversary or insider threat may want to modify a malware filter rule to evade detection.

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211

M365 Exchange Inbox Phishing Evasion Rule Created

Identifies when a user creates a new inbox rule in Microsoft 365 that deletes or moves emails containing suspicious keywords. Adversaries who have compromised accounts often create inbox rules to hide alerts, security notifications, or other sensitive messages by automatically deleting them or moving them to obscure folders. Common destinations include Deleted Items, Junk Email, RSS Feeds, and RSS Subscriptions. This is a New Terms rule that triggers only when the user principal name and associated source IP address have not been observed performing this activity in the past 14 days.

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2

M365 Exchange Email Safe Attachment Rule Disabled

Identifies when a safe attachment rule is disabled in Microsoft 365. Safe attachment rules can extend malware protections to include routing all messages and attachments without a known malware signature to a special hypervisor environment. An adversary or insider threat may disable a safe attachment rule to exfiltrate data or evade defenses.

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211

M365 Teams Custom Application Interaction Enabled

Identifies when custom applications are allowed in Microsoft Teams. If an organization requires applications other than those available in the Teams app store, custom applications can be developed as packages and uploaded. An adversary may abuse this behavior to establish persistence in an environment.

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212

M365 Teams External Access Enabled

Identifies when external access is enabled in Microsoft Teams. External access lets Teams and Skype for Business users communicate with other users that are outside their organization. An adversary may enable external access or add an allowed domain to exfiltrate data or maintain persistence in an environment.

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211

M365 Exchange Mail Flow Transport Rule Created

Identifies a transport rule creation in Microsoft 365. As a best practice, Exchange Online mail transport rules should not be set to forward email to domains outside of your organization. An adversary may create transport rules to exfiltrate data.

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211

M365 Exchange Mail Flow Transport Rule Modified

Identifies when a transport rule has been disabled or deleted in Microsoft 365. Mail flow rules (also known as transport rules) are used to identify and take action on messages that flow through your organization. An adversary or insider threat may modify a transport rule to exfiltrate data or evade defenses.

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211

M365 Security Compliance Potential Ransomware Activity

Identifies when Microsoft Cloud App Security reports that a user has uploaded files to the cloud that might be infected with ransomware.

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211

M365 Security Compliance Unusual Volume of File Deletion

Identifies that a user has deleted an unusually large volume of files as reported by Microsoft Cloud App Security.

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211

M365 Identity OAuth Illicit Consent Grant by Rare Client and User

Identifies an Microsoft 365 illicit consent grant request on-behalf-of a registered Entra ID application. Adversaries may create and register an application in Microsoft Entra ID for the purpose of requesting user consent to access resources in Microsoft 365. This is accomplished by tricking a user into granting consent to the application, typically via a pre-made phishing URL. This establishes an OAuth grant that allows the malicious client applocation to access resources in Microsoft 365 on-behalf-of the user.

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6

M365 Identity OAuth Phishing via First-Party Microsoft Application

Detects potentially suspicious OAuth authorization activity in Microsoft 365 where first-party Microsoft applications from the FOCI (Family of Client IDs) group request access to Microsoft Graph or legacy Azure AD resources. Developer tools like Azure CLI, Visual Studio Code, and Azure PowerShell accessing these resources are flagged, as they are commonly abused in phishing campaigns like ConsentFix. Additionally, any FOCI family application accessing the deprecated Windows Azure Active Directory resource is flagged since this API is rarely used legitimately and attackers target it for stealth. First-party apps are trusted by default in all tenants and cannot be blocked, making them ideal for OAuth phishing attacks.

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3

M365 Security Compliance Email Reported by User as Malware or Phish

Detects the occurrence of emails reported as Phishing or Malware by Users. Security Awareness training is essential to stay ahead of scammers and threat actors, as security products can be bypassed, and the user can still receive a malicious message. Educating users to report suspicious messages can help identify gaps in security controls and prevent malware infections and Business Email Compromise attacks.

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211

M365 Security Compliance User Restricted from Sending Email

Identifies when a user has been restricted from sending email due to exceeding sending limits of the service policies per the Security Compliance Center.

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211

M365 OneDrive Malware File Upload

Identifies the occurence of files uploaded to OneDrive being detected as Malware by the file scanning engine. Attackers can use File Sharing and Organization Repositories to spread laterally within the company and amplify their access. Users can inadvertently share these files without knowing their maliciousness, giving adversaries opportunity to gain initial access to other endpoints in the environment.

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211

M365 SharePoint Malware File Detected

Identifies the occurence of files uploaded to SharePoint being detected as Malware by the file scanning engine. Attackers can use File Sharing and Organization Repositories to spread laterally within the company and amplify their access. Users can inadvertently share these files without knowing their maliciousness, giving adversaries opportunities to gain initial access to other endpoints in the environment.

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211

M365 Identity Global Administrator Role Assigned

Identifies when the Microsoft 365 Global Administrator or Company Administrator role is assigned to a user or service principal. The Global Administrator role has extensive privileges across Entra ID and Microsoft 365 services, making it a high-value target for adversaries seeking persistent access. Successful assignments of this role may indicate potential privilege escalation or unauthorized access attempts, especially if performed by accounts that do not typically manage high-privilege roles.

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213

M365 Exchange Management Group Role Assigned

Identifies when a new role is assigned to a management group in Microsoft 365. An adversary may attempt to add a role in order to maintain persistence in an environment.

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211

M365 Exchange Mailbox High-Risk Permission Delegated

Identifies the assignment of rights to access content from another mailbox. An adversary may use the compromised account to send messages to other accounts in the network of the target organization while creating inbox rules, so messages can evade spam/phishing detection mechanisms.

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212

M365 Teams Guest Access Enabled

Identifies when guest access is enabled in Microsoft Teams. Guest access in Teams allows people outside the organization to access teams and channels. An adversary may enable guest access to maintain persistence in an environment.

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211

M365 Exchange Federated Domain Created or Modified

Identifies a new or modified federation domain, which can be used to create a trust between O365 and an external identity provider.

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212

Okta Sign-In Events via Third-Party IdP

Detects sign-in events where authentication is carried out via a third-party Identity Provider (IdP) that has not been seen before. Adversaries may add an unauthorized IdP to an Okta tenant to gain persistent access. This rule uses New Terms detection to only alert when a previously unseen IdP is used for authentication, reducing noise from legitimate federated identity providers while highlighting potentially rogue IdP additions.

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211

Machine Learning Detected a Suspicious Windows Event with a High Malicious Probability Score

A supervised machine learning model (ProblemChild) has identified a suspicious Windows process event with high probability of it being malicious activity. Alternatively, the model’s blocklist identified the event as being malicious.

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115

Machine Learning Detected a Suspicious Windows Event with a Low Malicious Probability Score

A supervised machine learning model (ProblemChild) has identified a suspicious Windows process event with low probability of it being malicious activity. Alternatively, the model’s blocklist identified the event as being malicious.

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13

Linux Clipboard Activity Detected

This rule monitors for the usage of the most common clipboard utilities on unix systems by an uncommon process parent. Adversaries may collect data stored in the clipboard from users copying information within or between applications.

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9

AWS CLI Command with Custom Endpoint URL

Detects the use of the AWS CLI with the "--endpoint-url" argument, which allows users to specify a custom endpoint URL for AWS services. This can be leveraged by adversaries to redirect API requests to non-standard or malicious endpoints, potentially bypassing typical security controls and logging mechanisms. This behavior may indicate an attempt to interact with unauthorized or compromised infrastructure, exfiltrate data, or perform other malicious activities under the guise of legitimate AWS operations.

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6

Network Activity Detected via cat

This rule monitors for the execution of the cat command, followed by a connection attempt by the same process. Cat is capable of transfering data via tcp/udp channels by redirecting its read output to a /dev/tcp or /dev/udp channel. This activity is highly suspicious, and should be investigated. Attackers may leverage this capability to transfer tools or files to another host in the network or exfiltrate data while attempting to evade detection in the process.

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11

Curl SOCKS Proxy Activity from Unusual Parent

This rule detects the use of the "curl" command-line tool with SOCKS proxy options, launched from an unusual parent process. Attackers may use "curl" to establish a SOCKS proxy connection to bypass network restrictions and exfiltrate data or communicate with C2 servers.

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6

High Number of Egress Network Connections from Unusual Executable

This rule detects a high number of egress network connections from an unusual executable on a Linux system. This could indicate a command and control (C2) communication attempt, a brute force attack via a malware infection, or other malicious activity. ESQL rules have limited fields available in its alert documents. Make sure to review the original documents to aid in the investigation of this alert.

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9

Git Repository or File Download to Suspicious Directory

This rule detects the use of git to clone a repository or download files from GitHub using wget or curl, followed by the creation of files in suspicious directories such as /tmp, /var/tmp, or /dev/shm. This behavior may indicate an attempt to download a payload, exploit or tool.

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3

IPv4/IPv6 Forwarding Activity

This rule monitors for the execution of commands that enable IPv4 and IPv6 forwarding on Linux systems. Enabling IP forwarding can be used to route network traffic between different network interfaces, potentially allowing attackers to pivot between networks, exfiltrate data, or establish command and control channels.

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107

Potential Protocol Tunneling via Chisel Client

This rule monitors for common command line flags leveraged by the Chisel client utility followed by a connection attempt. Chisel is a command-line utility used for creating and managing TCP and UDP tunnels, enabling port forwarding and secure communication between machines. Attackers can abuse the Chisel utility to establish covert communication channels, bypass network restrictions, and carry out malicious activities by creating tunnels that allow unauthorized access to internal systems.

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11

Deprecated - Potential Protocol Tunneling via Chisel Server

This rule monitors for common command line flags leveraged by the Chisel server utility followed by a received connection within a timespan of 1 minute. Chisel is a command-line utility used for creating and managing TCP and UDP tunnels, enabling port forwarding and secure communication between machines. Attackers can abuse the Chisel utility to establish covert communication channels, bypass network restrictions, and carry out malicious activities by creating tunnels that allow unauthorized access to internal systems.

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11

ProxyChains Activity

This rule monitors for the execution of the ProxyChains utility. ProxyChains is a command-line tool that enables the routing of network connections through intermediary proxies, enhancing anonymity and enabling access to restricted resources. Attackers can exploit the ProxyChains utility to hide their true source IP address, evade detection, and perform malicious activities through a chain of proxy servers, potentially masking their identity and intentions.

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109

Suspicious Utility Launched via ProxyChains

This rule monitors for the execution of suspicious linux tools through ProxyChains. ProxyChains is a command-line tool that enables the routing of network connections through intermediary proxies, enhancing anonymity and enabling access to restricted resources. Attackers can exploit the ProxyChains utility to hide their true source IP address, evade detection, and perform malicious activities through a chain of proxy servers, potentially masking their identity and intentions.

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112

Potential Linux Tunneling and/or Port Forwarding

This rule monitors for a set of Linux utilities that can be used for tunneling and port forwarding. Attackers can leverage tunneling and port forwarding techniques to bypass network defenses, establish hidden communication channels, and gain unauthorized access to internal resources, facilitating data exfiltration, lateral movement, and remote control.

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113

Potential Linux Tunneling and/or Port Forwarding via SSH Option

This rule detects the use of SSH options that may indicate tunneling or port forwarding on Linux systems. This behavior is commonly associated with malicious activity, such as establishing a port forward, proxy or an encrypted tunnel to exfiltrate data.

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3

Linux Telegram API Request

This rule detects when a process executes the curl or wget command with an argument that includes the api.telegram.org domain. This may indicate command and control behavior.

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4

Potential Protocol Tunneling via EarthWorm

Identifies the execution of the EarthWorm tunneler. Adversaries may tunnel network communications to and from a victim system within a separate protocol to avoid detection and network filtering, or to enable access to otherwise unreachable systems.

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215

AWS Credentials Searched For Inside A Container

This rule detects the use of system search utilities like grep and find to search for AWS credentials inside a container. Unauthorized access to these sensitive files could lead to further compromise of the container environment or facilitate a container breakout to the underlying cloud environment.

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3

Sensitive Files Compression

Identifies the use of a compression utility to collect known files containing sensitive information, such as credentials and system configurations.

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212

Sensitive Files Compression Inside A Container

Identifies the use of a compression utility to collect known files containing sensitive information, such as credentials and system configurations inside a container.

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3

Potential Linux Credential Dumping via Unshadow

Identifies the execution of the unshadow utility which is part of John the Ripper, a password-cracking tool on the host machine. Malicious actors can use the utility to retrieve the combined contents of the /etc/shadow and /etc/password files. Using the combined file generated from the utility, the malicious threat actors can use them as input for password-cracking utilities or prepare themselves for future operations by gathering credential information of the victim.

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113

Linux init (PID 1) Secret Dump via GDB

This rule monitors for the potential memory dump of the init process (PID 1) through gdb. Attackers may leverage memory dumping techniques to attempt secret extraction from privileged processes. Tools that display this behavior include "truffleproc" and "bash-memory-dump". This behavior should not happen by default, and should be investigated thoroughly.

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111

GitHub Authentication Token Access via Node.js

This rule detects when the Node.js runtime spawns a shell to execute the GitHub CLI (gh) command to retrieve a GitHub authentication token. The GitHub CLI is a command-line tool that allows users to interact with GitHub from the terminal. The "gh auth token" command is used to retrieve an authentication token for GitHub, which can be used to authenticate API requests and perform actions on behalf of the user. Adversaries may use this technique to access GitHub repositories and potentially exfiltrate sensitive information or perform malicious actions. This activity was observed in the wild as part of the Shai-Hulud worm.

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3

Kubernetes Service Account Secret Access

This rule detects when a process accesses Kubernetes service account secrets. Kubernetes service account secrets are files that contain sensitive information used by applications running in Kubernetes clusters to authenticate and authorize access to the cluster. These secrets are typically mounted into pods at runtime, allowing applications to access them securely. Unauthorized access to these secrets can lead to privilege escalation, lateral movement and unauthorized actions within the cluster.

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3

Manual Memory Dumping via Proc Filesystem

This rule monitors for manual memory dumping via the proc filesystem. The proc filesystem in Linux provides a virtual filesystem that contains information about system processes and their memory mappings. Attackers may use this technique to dump the memory of a process, potentially extracting sensitive information such as credentials or encryption keys.

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3

Potential Linux Local Account Brute Force Detected

Identifies multiple consecutive login attempts executed by one process targeting a local linux user account within a short time interval. Adversaries might brute force login attempts across different users with a default wordlist or a set of customly crafted passwords in an attempt to gain access to these accounts.

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13

Potential External Linux SSH Brute Force Detected

Identifies multiple external consecutive login failures targeting a user account from the same source address within a short time interval. Adversaries will often brute force login attempts across multiple users with a common or known password, in an attempt to gain access to these accounts.

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11

Potential Internal Linux SSH Brute Force Detected

Identifies multiple internal consecutive login failures targeting a user account from the same source address within a short time interval. Adversaries will often brute force login attempts across multiple users with a common or known password, in an attempt to gain access to these accounts.

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15

Deprecated - Potential Successful Linux FTP Brute Force Attack Detected

An FTP (file transfer protocol) brute force attack is a method where an attacker systematically tries different combinations of usernames and passwords to gain unauthorized access to an FTP server, and if successful, the impact can include unauthorized data access, manipulation, or theft, compromising the security and integrity of the server and potentially exposing sensitive information. This rule identifies multiple consecutive authentication failures targeting a specific user account from the same source address and within a short time interval, followed by a successful authentication.

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11

Deprecated - Potential Successful Linux RDP Brute Force Attack Detected

An RDP (Remote Desktop Protocol) brute force attack involves an attacker repeatedly attempting various username and password combinations to gain unauthorized access to a remote computer via RDP, and if successful, the potential impact can include unauthorized control over the compromised system, data theft, or the ability to launch further attacks within the network, jeopardizing the security and confidentiality of the targeted system and potentially compromising the entire network infrastructure. This rule identifies multiple consecutive authentication failures targeting a specific user account within a short time interval, followed by a successful authentication.

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11

Potential Successful SSH Brute Force Attack

Identifies multiple SSH login failures followed by a successful one from the same source address. Adversaries can attempt to login into multiple users with a common or known password to gain access to accounts.

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15

Potential Linux Credential Dumping via Proc Filesystem

Identifies the execution of the mimipenguin exploit script which is linux adaptation of Windows tool mimikatz. Mimipenguin exploit script is used to dump clear text passwords from a currently logged-in user. The tool exploits a known vulnerability CVE-2018-20781. Malicious actors can exploit the cleartext credentials in memory by dumping the process and extracting lines that have a high probability of containing cleartext passwords.

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112

Sensitive Keys Or Passwords Searched For Inside A Container

This rule detects the use of system search utilities like grep and find to search for private SSH keys or passwords inside a container. Unauthorized access to these sensitive files could lead to further compromise of the container environment or facilitate a container breakout to the underlying host machine.

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3

Potential OpenSSH Backdoor Logging Activity

Identifies a Secure Shell (SSH) client or server process creating a known SSH backdoor log file. Adversaries may modify SSH related binaries for persistence or credential access via patching sensitive functions to enable unauthorized access or to log SSH credentials for exfiltration.

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214

Access Control List Modification via setfacl

This rule detects Linux Access Control List (ACL) modification via the setfacl command. Attackers may use the setfacl utility to modify file and directory permissions in order to evade detection and maintain persistence on a compromised system.

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107

Attempt to Disable Auditd Service

Adversaries may attempt to disable the Auditd service to evade detection. Auditd is a Linux service that provides system auditing and logging. Disabling the Auditd service can prevent the system from logging important security events, which can be used to detect malicious activity.

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105

Attempt to Disable IPTables or Firewall

Adversaries may attempt to disable the iptables or firewall service in an attempt to affect how a host is allowed to receive or send network traffic.

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114

Attempt to Disable Syslog Service

Syslog is a critical component in Linux environments, responsible for logging system events and activities. Adversaries may attempt to disable the syslog service to disrupt event logging and evade detection by security controls.

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216

SSH Authorized Keys File Deletion

This rule detects the deletion of the authorized_keys or authorized_keys2 files on Linux systems. These files are used to store public keys for SSH authentication. Unauthorized deletion of these files can be an indicator of an attacker removing access to the system, and may be a precursor to further malicious activity.

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5

Base16 or Base32 Encoding/Decoding Activity

Base16 and Base32 are encoding schemes that convert binary data into text, making it easier to transmit and store. This rule monitors for Base16 or Base32 encoding and decoding activity on Linux systems. Attackers may use these encoding schemes to obfuscate malicious payloads, evade detection, and facilitate data exfiltration.

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215

Unusual Base64 Encoding/Decoding Activity

This rule leverages ESQL to detect unusual base64 encoding/decoding activity on Linux systems. Attackers may use base64 encoding/decoding to obfuscate data, such as command and control traffic or payloads, to evade detection by host- or network-based security controls. ESQL rules have limited fields available in its alert documents. Make sure to review the original documents to aid in the investigation of this alert.

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8

System Binary Moved or Copied

This rule monitors for the copying or moving of a system binary. Adversaries may copy/move and rename system binaries to evade detection. Copying a system binary to a different location should not occur often, so if it does, the activity should be investigated.

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18

File made Immutable by Chattr

Detects a file being made immutable using the chattr binary. Making a file immutable means it cannot be deleted or renamed, no link can be created to this file, most of the file’s metadata can not be modified, and the file can not be opened in write mode. Threat actors will commonly utilize this to prevent tampering or modification of their malicious files or any system files they have modified for purposes of persistence (e.g .ssh, /etc/passwd, etc.).

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217

Attempt to Clear Kernel Ring Buffer

Monitors for the deletion of the kernel ring buffer events through dmesg. Attackers may clear kernel ring buffer events to evade detection after installing a Linux kernel module (LKM). This activity is commonly observed by intrusions that leverage kernel-level rootkits to maintain persistence on a compromised host.

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110

Hidden Files and Directories via Hidden Flag

Identify activity related where adversaries can add the hidden flag to files to hide them from the user in an attempt to evade detection. This behavior is often observed in attempts to conceal malicious files or maintain persistence on a compromised system.

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108

Directory Creation in /bin directory

This rule identifies the creation of directories in the /bin directory. The /bin directory contains essential binary files that are required for the system to function properly. The creation of directories in this location could be an attempt to hide malicious files or executables, as these /bin directories usually just contain binaries.

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106

Potential Disabling of AppArmor

This rule monitors for potential attempts to disable AppArmor. AppArmor is a Linux security module that enforces fine-grained access control policies to restrict the actions and resources that specific applications and processes can access. Adversaries may disable security tools to avoid possible detection of their tools and activities.

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112

Potential Disabling of SELinux

Identifies potential attempts to disable Security-Enhanced Linux (SELinux), which is a Linux kernel security feature to support access control policies. Adversaries may disable security tools to avoid possible detection of their tools and activities.

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215

Potential Defense Evasion via Doas

This rule detects the creation or rename of the Doas configuration file on a Linux system. Adversaries may create or modify the Doas configuration file to elevate privileges and execute commands as other users while attempting to evade detection.

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105

Dynamic Linker Creation

Detects the creation of files related to the configuration of the dynamic linker on Linux systems. The dynamic linker is a shared library that is used by the Linux kernel to load and execute programs. Attackers may attempt to hijack the execution flow of a program by modifying the dynamic linker configuration files. This technique is often observed by userland rootkits that leverage shared objects to maintain persistence on a compromised host.

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8

File Deletion via Shred

Malware or other files dropped or created on a system by an adversary may leave traces behind as to what was done within a network and how. Adversaries may remove these files over the course of an intrusion to keep their footprint low or remove them at the end as part of the post-intrusion cleanup process.

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215

File Permission Modification in Writable Directory

Identifies file permission modifications in common writable directories by a non-root user. Adversaries often drop files or payloads into a writable directory and change permissions prior to execution.

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215

Potential Hex Payload Execution via Command-Line

This rule detects when a process executes a command line containing hexadecimal characters. Malware authors may use hexadecimal encoding to obfuscate their payload and evade detection.

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4

Potential Hex Payload Execution via Common Utility

This rule detects potential hex payload execution on Linux systems. Adversaries may use hex encoding to obfuscate payloads and evade detection mechanisms.

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106

Hidden Directory Creation via Unusual Parent

This rule detects the creation of a hidden directory via an unusual parent executable. Hidden directories are directories that are not visible to the user by default. They are often used by attackers to hide malicious files or tools.

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106

Creation of Hidden Files and Directories via CommandLine

Users can mark specific files as hidden simply by putting a "." as the first character in the file or folder name. Adversaries can use this to their advantage to hide files and folders on the system for persistence and defense evasion. This rule looks for hidden files or folders in common writable directories.

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116

Creation of Hidden Shared Object File

Identifies the creation of a hidden shared object (.so) file. Users can mark specific files as hidden simply by putting a "." as the first character in the file or folder name. Adversaries can use this to their advantage to hide files and folders on the system for persistence and defense evasion.

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215

Unusual Interactive Shell Launched from System User

This rule detects interactive shells launched from system users. System users typically do not require interactive shells, and their presence may indicate malicious activity.

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5

Base64 Decoded Payload Piped to Interpreter

This rule detects when a base64 decoded payload is piped to an interpreter on Linux systems. Adversaries may use base64 encoding to obfuscate data and pipe it to an interpreter to execute malicious code. This technique may be used to evade detection by host- or network-based security controls.

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5

Attempt to Clear Logs via Journalctl

This rule monitors for attempts to clear logs using the "journalctl" command on Linux systems. Adversaries may use this technique to cover their tracks by deleting or truncating log files, making it harder for defenders to investigate their activities. The rule looks for the execution of "journalctl" with arguments that indicate log clearing actions, such as "--vacuum-time", "--vacuum-size", or "--vacuum-files".

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2

Kernel Module Removal

Kernel modules are pieces of code that can be loaded and unloaded into the kernel upon demand. They extend the functionality of the kernel without the need to reboot the system. This rule identifies attempts to remove a kernel module.

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215

Kill Command Execution

This rule detects the execution of kill, pkill, and killall commands on Linux systems. These commands are used to terminate processes on a system. Attackers may use these commands to kill security tools or other processes to evade detection or disrupt system operations.

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5

Executable Masquerading as Kernel Process

Monitors for kernel processes with associated process executable fields that are not empty. Unix kernel processes such as kthreadd and kworker typically do not have process.executable fields associated to them. Attackers may attempt to hide their malicious programs by masquerading as legitimate kernel processes.

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108

Unusual LD_PRELOAD/LD_LIBRARY_PATH Command Line Arguments

This rule detects the use of the LD_PRELOAD and LD_LIBRARY_PATH environment variables in a command line argument. This behavior is unusual and may indicate an attempt to hijack the execution flow of a process. Threat actors may use this technique to evade defenses, escalate privileges, or maintain persistence on a system.

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4

Dynamic Linker (ld.so) Creation

This rule detects the creation of the dynamic linker (ld.so). The dynamic linker is used to load shared libraries needed by an executable. Attackers may attempt to replace the dynamic linker with a malicious version to execute arbitrary code.

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106

System Log File Deletion

Identifies the deletion of sensitive Linux system logs. This may indicate an attempt to evade detection or destroy forensic evidence on a system.

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217

Potential Hidden Process via Mount Hidepid

Identifies the execution of mount process with hidepid parameter, which can make processes invisible to other users from the system. Adversaries using Linux kernel version 3.2+ (or RHEL/CentOS v6.5+ above) can hide the process from other users. When hidepid=2 option is executed to mount the /proc filesystem, only the root user can see all processes and the logged-in user can only see their own process. This provides a defense evasion mechanism for the adversaries to hide their process executions from all other commands such as ps, top, pgrep and more. With the Linux kernel hardening hidepid option all the user has to do is remount the /proc filesystem with the option, which can now be monitored and detected.

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114

Multi-Base64 Decoding Attempt from Suspicious Location

This rule detects the execution of multiple base64 decoding commands to decode data. multi-decoded data is suspicious, and may be used by attackers to obfuscate malicious payloads or commands.

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2

Potential Impersonation Attempt via Kubectl

This rule detects potential impersonation attempts via the "kubectl" command in Linux environments. It identifies process events where "kubectl" is executed with arguments that suggest an attempt to impersonate another user or group, such as using "--kubeconfig", "--token", "--as", or "--as-group". This could indicate an adversary trying to gain unauthorized access or escalate privileges within a Kubernetes cluster. If this rule is triggered, in conjunction with rules related to secret access or kubeconfig file discovery, it may indicate a potential impersonation attempt.

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2

Potential Kubectl Masquerading via Unexpected Process

This rule detects potential kubectl masquerading activity by monitoring for process events where the process name is not "kubectl" but the command line arguments include kubectl-related commands. This could indicate an adversary attempting to masquerade as legitimate kubectl activity to evade detection. This rule covers evasion gaps introduced by renaming the kubectl binary, or placing it in an unusual directory.

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2

Potential Defense Evasion via PRoot

Identifies the execution of the PRoot utility, an open-source tool for user-space implementation of chroot, mount --bind, and binfmt_misc. Adversaries can leverage an open-source tool PRoot to expand the scope of their operations to multiple Linux distributions and simplify their necessary efforts. In a normal threat scenario, the scope of an attack is limited by the varying configurations of each Linux distribution. With PRoot, it provides an attacker with a consistent operational environment across different Linux distributions, such as Ubuntu, Fedora, and Alpine. PRoot also provides emulation capabilities that allow for malware built on other architectures, such as ARM, to be run.The post-exploitation technique called bring your own filesystem (BYOF), can be used by the threat actors to execute malicious payload or elevate privileges or perform network scans or orchestrate another attack on the environment. Although PRoot was originally not developed with malicious intent it can be easily tuned to work for one.

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112

Potential Process Name Stomping with Prctl

This rule leverages Auditd data to detect the use of the "prctl" syscall to potentially hide a process by changing its name. The "prctl" syscall is used to control various process attributes. Attackers can use this syscall to change the name of a process to a hidden directory or file, making it harder to detect. The query looks for the "prctl" syscall with the "PR_SET_NAME" argument set to "f" (PR_SET_NAME is used to set the name of a process).

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6

Suspicious Renaming of ESXI Files

Identifies instances where VMware-related files, such as those with extensions like ".vmdk", ".vmx", ".vmxf", ".vmsd", ".vmsn", ".vswp", ".vmss", ".nvram", and ".vmem", are renamed on a Linux system. The rule monitors for the "rename" event action associated with these file types, which could indicate malicious activity.

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12

Deprecated - Suspicious Renaming of ESXI index.html File

Identifies instances where the "index.html" file within the "/usr/lib/vmware/*" directory is renamed on a Linux system. The rule monitors for the "rename" event action associated with this specific file and path, which could indicate malicious activity.

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12

Root Certificate Installation

This rule detects the installation of root certificates on a Linux system. Adversaries may install a root certificate on a compromised system to avoid warnings when connecting to their command and control servers. Root certificates are used in public key cryptography to identify a root certificate authority (CA). When a root certificate is installed, the system or application will trust certificates in the root’s chain of trust that have been signed by the root certificate.

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106

SELinux Configuration Creation or Renaming

This rule detects the creation or renaming of the SELinux configuration file. SELinux is a security module that provides access control security policies. Modifications to the SELinux configuration file may indicate an attempt to impair defenses by disabling or modifying security tools.

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105

SSL Certificate Deletion

This rule detects the deletion of SSL certificates on a Linux system. Adversaries may delete SSL certificates to subvert trust controls and negatively impact the system.

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105

Potentially Suspicious Process Started via tmux or screen

This rule monitors for the execution of suspicious commands via screen and tmux. When launching a command and detaching directly, the commands will be executed in the background via its parent process. Attackers may leverage screen or tmux to execute commands while attempting to evade detection.

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110

Suspicious Path Mounted

This rule detects suspicious paths mounted on Linux systems. The mount command is used to attach filesystems to the system, and attackers may use it to mount malicious filesystems or directories for data exfiltration or persistence.

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3

System Binary Symlink to Suspicious Location

This rule detects the creation of a symbolic link from a system binary to a suspicious and writable location. This activity may indicate an attacker’s attempt to evade detection by behavioral rules that depend on predefined process parent/child relationships. By executing the symlinked variant of a binary instead of the original, the attacker aims to bypass these rules. Through the new_terms rule type, this rule can identify uncommon parent processes that may indicate the presence of a malicious symlink.

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3

Suspicious Kernel Feature Activity

This rule detects the modification and reading of kernel features through built-in commands. Attackers may collect information, disable or weaken Linux kernel protections. For example, an attacker may modify ASLR protection by disabling kernel.randomize_va_space, allow ptrace by setting kernel.yama.ptrace_scope to 0, or disable the NMI watchdog by setting kernel.nmi_watchdog to 0. These changes may be used to impair defenses and evade detection.

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4

Unusual Kill Signal

This rule detects the use of unusual kill signals, specifically kill signals in the range of 32-64, which are not commonly used in standard operations. Rootkits may leverage these signals to conduct certain actions, such as manipulating processes in unexpected ways, potentially escalating privileges or evading detection.

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2

Unusual Preload Environment Variable Process Execution

This rule detects processes that are executed with environment variables that are not commonly used. This could indicate an attacker is attempting to hijack the execution flow of a process by loading malicious libraries or binaries into the process memory space.

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5

File Creation in /var/log via Suspicious Process

This rule detects the creation of files in the /var/log/ directory via process executables located in world-writeable locations or via hidden processes. Attackers may attempt to hide their activities by creating files in the /var/log/ directory, which is commonly used for logging system events.

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4

Docker Socket Enumeration

This rule detects potential Docker socket enumeration activity by monitoring processes that attempt to interact with the Docker socket file (/var/run/docker.sock). Docker socket enumeration is a common technique used by attackers to interact with the Docker daemon and perform various operations, such as creating, starting, stopping, and removing containers. Attackers may abuse Docker socket enumeration to gain unauthorized access to the host system, escalate privileges, or move laterally within the environment.

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4

Suspicious Dynamic Linker Discovery via od

Monitors for dynamic linker discovery via the od utility. od (octal dump) is a command-line utility in Unix operating systems used for displaying data in various formats, including octal, hexadecimal, decimal, and ASCII, primarily used for examining and debugging binary files or data streams. Attackers can leverage od to analyze the dynamic linker by identifying injection points and craft exploits based on the observed behaviors and structures within these files.

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107

ESXI Discovery via Find

Identifies instances where the find command is started on a Linux system with arguments targeting specific VM-related paths, such as "/etc/vmware/", "/usr/lib/vmware/", or "/vmfs/*". These paths are associated with VMware virtualization software, and their presence in the find command arguments may indicate that a threat actor is attempting to search for, analyze, or manipulate VM-related files and configurations on the system.

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112

ESXI Discovery via Grep

Identifies instances where a process named grep, egrep, or pgrep is started on a Linux system with arguments related to virtual machine (VM) files, such as "vmdk", "vmx", "vmxf", "vmsd", "vmsn", "vswp", "vmss", "nvram", or "vmem". These file extensions are associated with VM-related file formats, and their presence in grep command arguments may indicate that a threat actor is attempting to search for, analyze, or manipulate VM files on the system.

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112

Unusual Kernel Module Enumeration

Loadable Kernel Modules (or LKMs) are pieces of code that can be loaded and unloaded into the kernel upon demand. They extend the functionality of the kernel without the need to reboot the system. This identifies attempts to enumerate information about a kernel module.

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214

Kernel Seeking Activity

This rule detects kernel seeking activity through several built-in Linux utilities. Attackers may use these utilities to search the Linux kernel for available symbols, functions, and other information that can be used to exploit the kernel.

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6

Kernel Unpacking Activity

This rule detects kernel unpacking activity through several built-in Linux utilities. Attackers may use these utilities to unpack kernel images and modules to search for vulnerabilities or to modify the kernel.

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6

Kubeconfig File Discovery

The kubeconfig file is a critical component in Kubernetes environments, containing configuration details for accessing and managing Kubernetes clusters. Attackers may attempt to get access to, create, or modify kubeconfig files to gain unauthorized initial access to Kubernetes clusters or move laterally within the cluster. This rule detects process discovery executions that involve kubeconfig files, particularly those executed from common shell environments or world-writeable directories.

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3

Kubectl Permission Discovery

This rule detects the use of the "kubectl auth --can-i" command, which is used to check permissions in Kubernetes clusters. Attackers may use this command to enumerate permissions and discover potential misconfigurations in the cluster, allowing them to gain unauthorized access or escalate privileges.

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4

Manual Mount Discovery via /etc/exports or /etc/fstab

This rule detects manual mount discovery via the /etc/exports or /etc/fstab file on Linux systems. These files are used by NFS (Network File System) to define which directories are shared with remote hosts. Attackers may access this file to gather information about shared directories and potential targets for further exploitation.

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3

Pluggable Authentication Module (PAM) Version Discovery

This rule detects PAM version discovery activity on Linux systems. PAM version discovery can be an indication of an attacker attempting to backdoor the authentication process through malicious PAM modules.

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106

Potential Network Scan Executed From Host

This threshold rule monitors for the rapid execution of unix utilities that are capable of conducting network scans. Adversaries may leverage built-in tools such as ping, netcat or socat to execute ping sweeps across the network while attempting to evade detection or due to the lack of network mapping tools available on the compromised host.

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7

Polkit Version Discovery

This rule detects Polkit version discovery activity on Linux systems. Polkit version discovery can be an indication of an attacker attempting to exploit misconfigurations or vulnerabilities in the Polkit service.

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6

Potential Port Scanning Activity from Compromised Host

This rule detects potential port scanning activity from a compromised host. Port scanning is a common reconnaissance technique used by attackers to identify open ports and services on a target system. A compromised host may exhibit port scanning behavior when an attacker is attempting to map out the network topology, identify vulnerable services, or prepare for further exploitation. This rule identifies potential port scanning activity by monitoring network connection attempts from a single host to a large number of ports within a short time frame. ESQL rules have limited fields available in its alert documents. Make sure to review the original documents to aid in the investigation of this alert.

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10

Private Key Searching Activity

This rule detects private key searching activity on Linux systems. Searching for private keys can be an indication of an attacker attempting to escalate privileges or exfiltrate sensitive information.

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106

Suspicious /proc/maps Discovery

Monitors for /proc//maps file reads. The /proc//maps file in Linux provides a memory map for a specific process, detailing the memory segments, permissions, and what files are mapped to these segments. Attackers may read a process’s memory map to identify memory addresses for code injection or process hijacking.

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8

Process Capability Enumeration

Identifies recursive process capability enumeration of the entire filesystem through the getcap command. Malicious users may manipulate identified capabilities to gain root privileges.

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8

Deprecated - Potential Pspy Process Monitoring Detected

This rule leverages auditd to monitor for processes scanning different processes within the /proc directory using the openat syscall. This is a strong indication for the usage of the pspy utility. Attackers may leverage the pspy process monitoring utility to monitor system processes without requiring root permissions, in order to find potential privilege escalation vectors.

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12

Security File Access via Common Utilities

This rule detects sensitive security file access via common utilities on Linux systems. Adversaries may attempt to read from sensitive files using common utilities to gather information about the system and its security configuration.

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106

Potential Subnet Scanning Activity from Compromised Host

This rule detects potential subnet scanning activity from a compromised host. Subnet scanning is a common reconnaissance technique used by attackers to identify live hosts within a network range. A compromised host may exhibit subnet scanning behavior when an attacker is attempting to map out the network topology, identify vulnerable hosts, or prepare for further exploitation. This rule identifies potential subnet scanning activity by monitoring network connection attempts from a single host to a large number of hosts within a short time frame. ESQL rules have limited fields available in its alert documents. Make sure to review the original documents to aid in the investigation of this alert.

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9

SUID/SGUID Enumeration Detected

This rule monitors for the usage of the "find" command in conjunction with SUID and SGUID permission arguments. SUID (Set User ID) and SGID (Set Group ID) are special permissions in Linux that allow a program to execute with the privileges of the file owner or group, respectively, rather than the privileges of the user running the program. In case an attacker is able to enumerate and find a binary that is misconfigured, they might be able to leverage this misconfiguration to escalate privileges by exploiting vulnerabilities or built-in features in the privileged program.

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11

Suspicious Memory grep Activity

Monitors for grep activity related to memory mapping. The /proc/*/maps file in Linux provides a memory map for a specific process, detailing the memory segments, permissions, and what files are mapped to these segments. Attackers may read a process’s memory map to identify memory addresses for code injection or process hijacking.

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108

Suspicious Network Tool Launched Inside A Container

This rule detects commonly abused network utilities running inside a container. Network utilities like nc, nmap, dig, tcpdump, ngrep, telnet, mitmproxy, zmap can be used for malicious purposes such as network reconnaissance, monitoring, or exploitation, and should be monitored closely within a container.

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3

Unusual User Privilege Enumeration via id

This rule monitors for a sequence of 20 "id" command executions within 1 second by the same parent process. This behavior is unusual, and may be indicative of the execution of an enumeration script such as LinPEAS or LinEnum. These scripts leverage the "id" command to enumerate the privileges of all users present on the system.

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9

Virtual Machine Fingerprinting

An adversary may attempt to get detailed information about the operating system and hardware. This rule identifies common locations used to discover virtual machine hardware by a non-root user. This technique has been used by the Pupy RAT and other malware.

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113

Yum/DNF Plugin Status Discovery

This rule detects the execution of the grep command with the plugins argument on Linux systems. This command is used to search for YUM/DNF configurations and/or plugins with an enabled state. This behavior may indicate an attacker is attempting to establish persistence in a YUM or DNF plugin.

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107

Abnormal Process ID or Lock File Created

Identifies the creation of a Process ID (PID), lock or reboot file created in temporary file storage paradigm (tmpfs) directory /var/run. On Linux, the PID files typically hold the process ID to track previous copies running and manage other tasks. Certain Linux malware use the /var/run directory for holding data, executables and other tasks, disguising itself or these files as legitimate PID files.

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218

Container Management Utility Run Inside A Container

This rule detects when a container management binary is run from inside a container. These binaries are critical components of many containerized environments, and their presence and execution in unauthorized containers could indicate compromise or a misconfiguration.

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4

File Creation by Cups or Foomatic-rip Child

This detection rule addresses multiple vulnerabilities in the CUPS printing system, including CVE-2024-47176, CVE-2024-47076, CVE-2024-47175, and CVE-2024-47177. Specifically, this rule detects suspicious file creation events executed by child processes of foomatic-rip. These flaws impact components like cups-browsed, libcupsfilters, libppd, and foomatic-rip, allowing remote unauthenticated attackers to manipulate IPP URLs or inject malicious data through crafted UDP packets or network spoofing. This can result in arbitrary command execution when a print job is initiated.

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106

Printer User (lp) Shell Execution

This detection rule addresses multiple vulnerabilities in the CUPS printing system, including CVE-2024-47176, CVE-2024-47076, CVE-2024-47175, and CVE-2024-47177. Specifically, this rule detects shell executions from the foomatic-rip parent process through the default printer user (lp). These flaws impact components like cups-browsed, libcupsfilters, libppd, and foomatic-rip, allowing remote unauthenticated attackers to manipulate IPP URLs or inject malicious data through crafted UDP packets or network spoofing. This can result in arbitrary command execution when a print job is initiated.

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9

Deprecated - Potential curl CVE-2023-38545 Exploitation

Detects potential exploitation of curl CVE-2023-38545 by monitoring for vulnerable command line arguments in conjunction with an unusual command line length. A flaw in curl version ⇐ 8.3 makes curl vulnerable to a heap based buffer overflow during the SOCKS5 proxy handshake. Upgrade to curl version >= 8.4 to patch this vulnerability. This exploit can be executed with and without the use of environment variables. For increased visibility, enable the collection of http_proxy, HTTPS_PROXY and ALL_PROXY environment variables based on the instructions provided in the setup guide of this rule.

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11

Egress Connection from Entrypoint in Container

This rule identifies a sequence of events where a process named "entrypoint.sh" is started in a container, followed by a network connection attempt. This sequence indicates a potential egress connection from an entrypoint in a container. An entrypoint is a command or script specified in the Dockerfile and executed when the container starts. Attackers can use this technique to establish a foothold in the environment, escape from a container to the host, or establish persistence.

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6

File Creation, Execution and Self-Deletion in Suspicious Directory

This rule monitors for the creation of a file, followed by its execution and self-deletion in a short timespan within a directory often used for malicious purposes by threat actors. This behavior is often used by malware to execute malicious code and delete itself to hide its tracks.

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10

Suspicious File Made Executable via Chmod Inside A Container

This rule detects when chmod or chown are used to add the execute permission to a file in a world-writeable directory, and inside of a container. Modifying file permissions to make a file executable could indicate malicious activity, as an attacker may attempt to run unauthorized or malicious code inside the container.

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3

Potential Upgrade of Non-interactive Shell

Identifies when a non-interactive terminal (tty) is being upgraded to a fully interactive shell. Attackers may upgrade a simple reverse shell to a fully interactive tty after obtaining initial access to a host, in order to obtain a more stable connection.

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108

Kubectl Apply Pod from URL

This rule detects the execution of the "kubectl apply" command with a URL argument. This command is often used to apply configurations or deploy resources in a Kubernetes cluster. Attackers may use this command to deploy malicious pods or modify existing ones, potentially leading to unauthorized access or data exfiltration.

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2

Kubernetes Direct API Request via Curl or Wget

This rule monitors for the execution of curl or wget commands that directly access Kubernetes API endpoints, which may indicate an attempt to interact with Kubernetes resources in a potentially unauthorized manner. This technique is often used by adversaries to gather information about the Kubernetes environment, such as secrets, config maps, and other sensitive data, without using the official Kubernetes client tools such as "kubectl".

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2

Netcat Listener Established via rlwrap

Monitors for the execution of a netcat listener via rlwrap. rlwrap is a readline wrapper, a small utility that uses the GNU Readline library to allow the editing of keyboard input for any command. This utility can be used in conjunction with netcat to gain a more stable reverse shell.

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108

Network Connection from Binary with RWX Memory Region

Monitors for the execution of a unix binary with read, write and execute memory region permissions, followed by a network connection. The mprotect() system call is used to change the access protections on a region of memory that has already been allocated. This syscall allows a process to modify the permissions of pages in its virtual address space, enabling or disabling permissions such as read, write, and execute for those pages. RWX permissions on memory is in many cases overly permissive, and should (especially in conjunction with an outbound network connection) be analyzed thoroughly.

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8

Network Connection via Recently Compiled Executable

This rule monitors a sequence involving a program compilation event followed by its execution and a subsequent network connection event. This behavior can indicate the set up of a reverse tcp connection to a command-and-control server. Attackers may spawn reverse shells to establish persistence onto a target system.

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11

Interactive Terminal Spawned via Perl

Identifies when a terminal (tty) is spawned via Perl. Attackers may upgrade a simple reverse shell to a fully interactive tty after obtaining initial access to a host.

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113

Privileged Docker Container Creation

This rule leverages the new_terms rule type to identify the creation of a potentially unsafe docker container from an unusual parent process. Attackers can use the "--privileged" flag to create containers with escalated privileges, which can lead to trivial privilege escalation, docker escaping and persistence. access.

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6

Process Backgrounded by Unusual Parent

This rule identifies processes that are backgrounded by an unusual parent process. This behavior may indicate a process attempting to evade detection by hiding its parent process.

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4

Binary Executed from Shared Memory Directory

Identifies the execution of a binary by root in Linux shared memory directories: (/dev/shm/, /run/shm/, /var/run/, /var/lock/). This activity is to be considered highly abnormal and should be investigated. Threat actors have placed executables used for persistence on high-uptime servers in these directories as system backdoors.

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115

Interactive Terminal Spawned via Python

Identifies when a terminal (tty) is spawned via Python. Attackers may upgrade a simple reverse shell to a fully interactive tty after obtaining initial access to a host.

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215

Web Server Spawned via Python

This rule identifies when a web server is spawned via Python. Attackers may use Python to spawn a web server to exfiltrate/infiltrate data or to move laterally within a network.

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106

Potential Code Execution via Postgresql

This rule monitors for suspicious activities that may indicate an attacker attempting to execute arbitrary code within a PostgreSQL environment. Attackers can execute code via PostgreSQL as a result of gaining unauthorized access to a public facing PostgreSQL database or exploiting vulnerabilities, such as remote command execution and SQL injection attacks, which can result in unauthorized access and malicious actions, and facilitate post-exploitation activities for unauthorized access and malicious actions.

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12

Linux Restricted Shell Breakout via Linux Binary(s)

Identifies the abuse of a Linux binary to break out of a restricted shell or environment by spawning an interactive system shell. The activity of spawning a shell from a binary is not common behavior for a user or system administrator, and may indicate an attempt to evade detection, increase capabilities or enhance the stability of an adversary.

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118

Openssl Client or Server Activity

This rule identifies when the openssl client or server is used to establish a connection. Attackers may use openssl to establish a secure connection to a remote server or to create a secure server to receive connections. This activity may be used to exfiltrate data or establish a command and control channel.

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107

Potential Reverse Shell via Background Process

Monitors for the execution of background processes with process arguments capable of opening a socket in the /dev/tcp channel. This may indicate the creation of a backdoor reverse connection, and should be investigated further.

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109

Potential Reverse Shell via Child

This detection rule identifies suspicious network traffic patterns associated with TCP reverse shell activity. This activity consists of a network event that is followed by the creation of a shell process with suspicious command line arguments. An attacker may establish a Linux TCP reverse shell to gain remote access to a target system.

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8

Potential Reverse Shell via Java

This detection rule identifies the execution of a Linux shell process from a Java JAR application post an incoming network connection. This behavior may indicate reverse shell activity via a Java application.

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13

Potential Reverse Shell via Suspicious Child Process

This detection rule detects the creation of a shell through a suspicious process chain. Any reverse shells spawned by the specified utilities that are initialized from a single process followed by a network connection attempt will be captured through this rule. Attackers may spawn reverse shells to establish persistence onto a target system.

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14

Potential Meterpreter Reverse Shell

This detection rule identifies a sample of suspicious Linux system file reads used for system fingerprinting, leveraged by the Metasploit Meterpreter shell to gather information about the target that it is executing its shell on. Detecting this pattern is indicative of a successful meterpreter shell connection.

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11

Potential Reverse Shell via Suspicious Binary

This detection rule detects the creation of a shell through a chain consisting of the execution of a suspicious binary (located in a commonly abused location or executed manually) followed by a network event and ending with a shell being spawned. Stageless reverse tcp shells display this behaviour. Attackers may spawn reverse shells to establish persistence onto a target system.

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12

Potential Reverse Shell

This detection rule identifies suspicious network traffic patterns associated with TCP reverse shell activity. This activity consists of a parent-child relationship where a network event is followed by the creation of a shell process. An attacker may establish a Linux TCP reverse shell to gain remote access to a target system.

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14

Potential Reverse Shell via UDP

This detection rule identifies suspicious network traffic patterns associated with UDP reverse shell activity. This activity consists of a sample of an execve, socket and connect syscall executed by the same process, where the auditd.data.a0-1 indicate a UDP connection, ending with an egress connection event. An attacker may establish a Linux UDP reverse shell to bypass traditional firewall restrictions and gain remote access to a target system covertly.

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11

Suspicious Content Extracted or Decompressed via Funzip

Identifies when suspicious content is extracted from a file and subsequently decompressed using the funzip utility. Malware may execute the tail utility using the "-c" option to read a sequence of bytes from the end of a file. The output from tail can be piped to funzip in order to decompress malicious code before it is executed. This behavior is consistent with malware families such as Bundlore.

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110

Suspicious System Commands Executed by Previously Unknown Executable

This rule monitors for the execution of several commonly used system commands executed by a previously unknown executable located in commonly abused directories. An alert from this rule can indicate the presence of potentially malicious activity, such as the execution of unauthorized or suspicious processes attempting to run malicious code. Detecting and investigating such behavior can help identify and mitigate potential security threats, protecting the system and its data from potential compromise.

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111

Suspicious Mining Process Creation Event

Identifies service creation events of common mining services, possibly indicating the infection of a system with a cryptominer.

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111

Suspicious Named Pipe Creation

This rule detects the creation of unusually labeled named pipes (FIFOs) by the mkfifo command, which is often used by attackers to establish persistence on a target system or to execute commands in the background. Through the new_terms rule type, this rule can identify uncommon process command lines that may indicate the presence of a malicious named pipe.

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4

System Binary Path File Permission Modification

This rule identifies file permission modification events on files located in common system binary paths. Adversaries may attempt to hide their payloads in the default Linux system directories, and modify the file permissions of these payloads prior to execution.

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6

BPF filter applied using TC

Detects when the tc (transmission control) binary is utilized to set a BPF (Berkeley Packet Filter) on a network interface. Tc is used to configure Traffic Control in the Linux kernel. It can shape, schedule, police and drop traffic. A threat actor can utilize tc to set a bpf filter on an interface for the purpose of manipulating the incoming traffic. This technique is not at all common and should indicate abnormal, suspicious or malicious activity.

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214

Unix Socket Connection

This rule monitors for inter-process communication via Unix sockets. Adversaries may attempt to communicate with local Unix sockets to enumerate application details, find vulnerabilities/configuration mistakes and potentially escalate privileges or set up malicious communication channels via Unix sockets for inter-process communication to attempt to evade detection.

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109

Unknown Execution of Binary with RWX Memory Region

Monitors for the execution of a previously unknown unix binary with read, write and execute memory region permissions. The mprotect() system call is used to change the access protections on a region of memory that has already been allocated. This syscall allows a process to modify the permissions of pages in its virtual address space, enabling or disabling permissions such as read, write, and execute for those pages. RWX permissions on memory is in many cases overly permissive, and should be analyzed thoroughly.

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7

Interactive Shell Launched via Unusual Parent Process in a Container

This rule detects when an interactive shell process is launched via an unusual parent processes inside a container. Interactive processes are typically run in the foreground and require user input, which is unusual behavior for a containerized environment. This activity could indicate an attacker attempting to gain access to the container environment or perform malicious actions.

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3

Suspicious Path Invocation from Command Line

This rule detects the execution of a PATH variable in a command line invocation by a shell process. This behavior is unusual and may indicate an attempt to execute a command from a non-standard location. This technique may be used to evade detection or perform unauthorized actions on the system.

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6

Unusual Pkexec Execution

This rule detects the execution of the pkexec command by a shell process. The pkexec command is used to execute programs as another user, typically as the superuser. Through the new_terms rule type, unusual executions of pkexec are identified, and may indicate an attempt to escalate privileges or perform unauthorized actions on the system.

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106

Potential Data Exfiltration Through Curl

Detects the use of curl to upload an archived file to an internet server. Threat actors often will collect data on a system and compress it in an archive file before exfiltrating the file back to their C2 server for review. Many threat actors have been seen utilizing curl to upload this archive file with the collected data to do this. Use of curl in this way while not inherently malicious should be considered highly abnormal and suspicious activity.

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4

Potential Data Splitting Detected

This rule looks for the usage of common data splitting utilities with specific arguments that indicate data splitting for exfiltration on Linux systems. Data splitting is a technique used by adversaries to split data into smaller parts to avoid detection and exfiltrate data.

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106

File Transfer Utility Launched from Unusual Parent

This rule leverages ESQL to detect the execution of unusual file transfer utilities on Linux systems. Attackers may use these utilities to exfiltrate data from a compromised system. ESQL rules have limited fields available in its alert documents. Make sure to review the original documents to aid in the investigation of this alert.

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9

Suspicious Data Encryption via OpenSSL Utility

Identifies when the openssl command-line utility is used to encrypt multiple files on a host within a short time window. Adversaries may encrypt data on a single or multiple systems in order to disrupt the availability of their target’s data and may attempt to hold the organization’s data to ransom for the purposes of extortion.

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11

Suspicious Termination of ESXI Process

Identifies instances where VMware processes, such as "vmware-vmx" or "vmx," are terminated on a Linux system by a "kill" command. The rule monitors for the "end" event type, which signifies the termination of a process. The presence of a "kill" command as the parent process for terminating VMware processes may indicate that a threat actor is attempting to interfere with the virtualized environment on the targeted system.

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12

Memory Swap Modification

This rule detects memory swap modification events on Linux systems. Memory swap modification can be used to manipulate the system’s memory and potentially impact the system’s performance. This behavior is commonly observed in malware that deploys miner software such as XMRig.

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107

Potential Malware-Driven SSH Brute Force Attempt

This detection identifies a Linux host that has potentially been infected with malware and is being used to conduct brute-force attacks against external systems over SSH (port 22 and common alternative SSH ports). The detection looks for a high volume of outbound connection attempts to non-private IP addresses from a single process. A compromised host may be part of a botnet or controlled by an attacker, attempting to gain unauthorized access to remote systems. This behavior is commonly observed in SSH brute-force campaigns where malware hijacks vulnerable machines to expand its attack surface. ESQL rules have limited fields available in its alert documents. Make sure to review the original documents to aid in the investigation of this alert.

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9

Potential Linux Ransomware Note Creation Detected

This rule identifies a sequence of a mass file encryption event in conjunction with the creation of a .txt file with a file name containing ransomware keywords executed by the same process in a 1 second timespan. Ransomware is a type of malware that encrypts a victim’s files or systems and demands payment (usually in cryptocurrency) in exchange for the decryption key. One important indicator of a ransomware attack is the mass encryption of the file system, after which a new file extension is added to the file.

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15

High Number of Process Terminations

This rule identifies a high number (10) of process terminations via pkill from the same host within a short time period.

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116

Successful SSH Authentication from Unusual SSH Public Key

This rule leverages the new_terms rule type to detect successful SSH authentications via a public key that has not been seen in the last 5 days. Public key authentication is a secure method for authenticating users to a server. Monitoring unusual public key authentication events can help detect unauthorized access attempts or suspicious activity on the system.

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5

Successful SSH Authentication from Unusual IP Address

This rule leverages the new_terms rule type to detect successful SSH authentications by an IP- address that has not been authenticated in the last 5 days. This behavior may indicate an attacker attempting to gain access to the system using a valid account.

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4

Successful SSH Authentication from Unusual User

This rule leverages the new_terms rule type to detect successful SSH authentications by a user who has not been authenticated in the last 5 days. This behavior may indicate an attacker attempting to gain access to the system using a valid account.

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4

Kubeconfig File Creation or Modification

The kubeconfig file is a critical component in Kubernetes environments, containing configuration details for accessing and managing Kubernetes clusters. Attackers may attempt to get access to, create or modify kubeconfig files to gain unauthorized initial access to Kubernetes clusters or move laterally within the cluster.

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3

Remote File Creation in World Writeable Directory

This rule detects the creation of a file in a world-writeable directory through a service that is commonly used for file transfer. This behavior is often associated with lateral movement and can be an indicator of an attacker attempting to move laterally within a network.

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5

Potential THC Tool Downloaded

Identifies processes that are capable of downloading files with command line arguments containing URLs to SSH-IT’s autonomous SSH worm. This worm intercepts outgoing SSH connections every time a user uses ssh.

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108

Deprecated - SSH Process Launched From Inside A Container

This rule detects an SSH or SSHD process executed from inside a container. This includes both the client ssh binary and server ssh daemon process. SSH usage inside a container should be avoided and monitored closely when necessary. With valid credentials an attacker may move laterally to other containers or to the underlying host through container breakout. They may also use valid SSH credentials as a persistence mechanism.

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3

Connection to External Network via Telnet

Telnet provides a command line interface for communication with a remote device or server. This rule identifies Telnet network connections to publicly routable IP addresses.

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212

Connection to Internal Network via Telnet

Telnet provides a command line interface for communication with a remote device or server. This rule identifies Telnet network connections to non-publicly routable IP addresses.

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212

Unusual Remote File Creation

This rule leverages the new_terms rule type to detect file creation via a commonly used file transfer service while excluding typical remote file creation activity. This behavior is often linked to lateral movement, potentially indicating an attacker attempting to move within a network.

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5

Suspicious APT Package Manager Execution

Detects suspicious process events executed by the APT package manager, potentially indicating persistence through an APT backdoor. In Linux, APT (Advanced Package Tool) is a command-line utility used for handling packages on Debian-based systems, providing functions for installing, updating, upgrading, and removing software along with managing package repositories. Attackers can backdoor APT to gain persistence by injecting malicious code into scripts that APT runs, thereby ensuring continued unauthorized access or control each time APT is used for package management.

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110

APT Package Manager Configuration File Creation

Detects file creation events in the configuration directory for the APT package manager. In Linux, APT (Advanced Package Tool) is a command-line utility used for handling packages on (by default) Debian-based systems, providing functions for installing, updating, upgrading, and removing software along with managing package repositories. Attackers can backdoor APT to gain persistence by injecting malicious code into scripts that APT runs, thereby ensuring continued unauthorized access or control each time APT is used for package management.

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8

Suspicious APT Package Manager Network Connection

Detects suspicious network events executed by the APT package manager, potentially indicating persistence through an APT backdoor. In Linux, APT (Advanced Package Tool) is a command-line utility used for handling packages on Debian-based systems, providing functions for installing, updating, upgrading, and removing software along with managing package repositories. Attackers can backdoor APT to gain persistence by injecting malicious code into scripts that APT runs, thereby ensuring continued unauthorized access or control each time APT is used for package management.

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9

At Job Created or Modified

This rule monitors for at jobs being created or renamed. Linux at jobs are scheduled tasks that can be leveraged by system administrators to set up scheduled tasks, but may be abused by malicious actors for persistence, privilege escalation and command execution. By creating or modifying cron job configurations, attackers can execute malicious commands or scripts at predefined intervals, ensuring their continued presence and enabling unauthorized activities.

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7

Boot File Copy

This rule detects the process of copying or moving files from or to the "/boot" directory on Linux systems. The "/boot" directory contains files that are essential for the system to boot, such as the kernel and initramfs images. Attackers may copy or move files to the "/boot" directory to modify the boot process, which can be leveraged to maintain access to the system.

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5

Suspicious Usage of bpf_probe_write_user Helper

This rule monitors the syslog log file for messages related to instances of a program using the "bpf_probe_write_user" helper. The "bpf_probe_write_user" helper is used to write data to user space from a BPF program. Unauthorized use of this helper can be indicative of an eBPF rootkit or other malicious activity.

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4

Chkconfig Service Add

Detects the use of the chkconfig binary to manually add a service for management by chkconfig. Threat actors may utilize this technique to maintain persistence on a system. When a new service is added, chkconfig ensures that the service has either a start or a kill entry in every runlevel and when the system is rebooted the service file added will run providing long-term persistence.

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218

Renaming of OpenSSH Binaries

Adversaries may modify SSH related binaries for persistence or credential access by patching sensitive functions to enable unauthorized access or by logging SSH credentials for exfiltration.

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114

Cron Job Created or Modified

This rule monitors for (ana)cron jobs being created or renamed. Linux cron jobs are scheduled tasks that can be leveraged by system administrators to set up scheduled tasks, but may be abused by malicious actors for persistence, privilege escalation and command execution. By creating or modifying cron job configurations, attackers can execute malicious commands or scripts at predefined intervals, ensuring their continued presence and enabling unauthorized activities.

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19

D-Bus Service Created

This rule detects the creation of D-Bus service files on Linux systems. D-Bus is a message bus system that provides a way for applications to talk to one another. D-Bus services are defined in service files that are typically located in default directories. The rule looks for the creation of service files that are not associated with known package managers or system services. Attackers may create malicious D-Bus services to establish persistence or escalate privileges on a system.

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6

Unusual D-Bus Daemon Child Process

This rule detects when an unusual child process is spawned from the dbus-daemon parent process. The dbus-daemon process is a message bus system that provides a way for applications to talk to each other. Attackers may abuse this process to execute malicious code or escalate privileges.

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5

DNF Package Manager Plugin File Creation

Detects file creation events in the plugin directories for the Yum package manager. In Linux, DNF (Dandified YUM) is a command-line utility used for handling packages on Fedora-based systems, providing functions for installing, updating, upgrading, and removing software along with managing package repositories. Attackers can backdoor DNF to gain persistence by injecting malicious code into plugins that DNF runs, thereby ensuring continued unauthorized access or control each time DNF is used for package management.

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107

DPKG Package Installed by Unusual Parent Process

This rule detects the installation of a Debian package (dpkg) by an unusual parent process. The dpkg command is used to install, remove, and manage Debian packages on a Linux system. Attackers can abuse the dpkg command to install malicious packages on a system.

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6

Unusual DPKG Execution

This rule detects the execution of the DPKG command by processes not associated with the DPKG package manager. The DPKG command is used to install, remove, and manage Debian packages on a Linux system. Attackers can abuse the DPKG command to install malicious packages on a system.

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7

Dracut Module Creation

This rule detects the creation of Dracut module files on Linux systems. Dracut is a tool used to generate an initramfs image that is used to boot the system. Dracut modules are scripts that are executed during the initramfs image generation process. Attackers may create malicious Dracut modules to execute arbitrary code at boot time, which can be leveraged to maintain persistence on a Linux system.

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5

Dynamic Linker Copy

Detects the copying of the Linux dynamic loader binary and subsequent file creation for the purpose of creating a backup copy. This technique was seen recently being utilized by Linux malware prior to patching the dynamic loader in order to inject and preload a malicious shared object file. This activity should never occur and if it does then it should be considered highly suspicious or malicious.

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214

Initramfs Extraction via CPIO

This rule detects the extraction of an initramfs image using the "cpio" command on Linux systems. The "cpio" command is used to create or extract cpio archives. Attackers may extract the initramfs image to modify the contents or add malicious files, which can be leveraged to maintain persistence on the system.

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6

Git Hook Command Execution

This rule detects the execution of a potentially malicious process from a Git hook. Git hooks are scripts that Git executes before or after events such as: commit, push, and receive. An attacker can abuse Git hooks to execute arbitrary commands on the system and establish persistence.

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107

Git Hook Created or Modified

This rule detects the creation or modification of a Git hook file on a Linux system. Git hooks are scripts that Git executes before or after events such as commit, push, and receive. They are used to automate tasks, enforce policies, and customize Git’s behavior. Attackers can abuse Git hooks to maintain persistence on a system by executing malicious code whenever a specific Git event occurs.

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107

Git Hook Egress Network Connection

This rule detects a suspicious egress network connection attempt from a Git hook script. Git hooks are scripts that Git executes before or after events such as: commit, push, and receive. An attacker can abuse these features to execute arbitrary commands on the system, establish persistence or to initialize a network connection to a remote server and exfiltrate data or download additional payloads.

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6

Git Hook Child Process

This rule detects child processes spawned by Git hooks. Git hooks are scripts that Git executes before or after events such as commit, push, and receive. The rule identifies child processes spawned by Git hooks that are not typically spawned by the Git process itself. This behavior may indicate an attacker attempting to hide malicious activity by leveraging the legitimate Git process to execute unauthorized commands.

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106

GRUB Configuration File Creation

This rule detects the creation of GRUB configuration files on Linux systems. The GRUB configuration file is used to configure the boot loader, which is responsible for loading the operating system. Attackers may create malicious GRUB configuration files to execute arbitrary code or escalate privileges during the boot process, which can be leveraged to maintain persistence on the system.

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5

GRUB Configuration Generation through Built-in Utilities

This rule detects the generation of a new GRUB configuration file using built-in Linux commands. The GRUB configuration file is used to configure the GRUB bootloader, which is responsible for loading the Linux kernel and initramfs image during the boot process. Attackers may use these built-in utilities to generate a new GRUB configuration file that includes malicious kernel parameters or boot options, which can be leveraged to maintain persistence on the system.

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5

System V Init Script Created

Files that are placed in the "/etc/init.d/" directory in Unix can be used to start custom applications, services, scripts or commands during start-up. Init.d has been mostly replaced in favor of Systemd. However, the "systemd-sysv-generator" can convert init.d files to service unit files that run at boot. Adversaries may add or alter files located in the "/etc/init.d/" directory to execute malicious code upon boot in order to gain persistence on the system.

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118

Kernel Module Load via insmod

Detects the use of the insmod binary to load a Linux kernel object file. Threat actors can use this binary, given they have root privileges, to load a rootkit on a system providing them with complete control and the ability to hide from security products. Manually loading a kernel module in this manner should not be at all common and can indicate suspcious or malicious behavior.

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215

KDE AutoStart Script or Desktop File Creation

Identifies the creation or modification of a K Desktop Environment (KDE) AutoStart script or desktop file that will execute upon each user logon. Adversaries may abuse this method for persistence.

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219

Kernel Driver Load by non-root User

Detects the loading of a Linux kernel module by a non-root user through system calls. Threat actors may leverage Linux kernel modules to load a rootkit on a system providing them with complete control and the ability to hide from security products. As other rules monitor for the addition of Linux kernel modules through system utilities or .ko files, this rule covers the gap that evasive rootkits leverage by monitoring for kernel module additions on the lowest level through auditd_manager.

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7

Kernel Object File Creation

This rule detects the creation of a Linux kernel object file (.ko) on a system. Threat actors may leverage Linux kernel object files to load a rootkit or other type of malware on a system providing them with complete control and the ability to hide from security products.

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5

Kubernetes Sensitive Configuration File Activity

This rule detects the creation or modification of sensitive Kubernetes configuration files on Linux systems. These files include Kubernetes manifests, PKI files, and configuration files that are critical for the operation of Kubernetes clusters. Monitoring these files helps identify potential unauthorized changes or misconfigurations that could lead to security vulnerabilities in Kubernetes environments. Attackers may attempt to modify these files to gain persistence or to deploy malicious containers within the Kubernetes cluster.

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2

Suspicious File Creation via Kworker

This rule monitors for a file creation event originating from a kworker parent process. kworker, or kernel worker, processes are part of the kernel’s workqueue mechanism. They are responsible for executing work that has been scheduled to be done in kernel space, which might include tasks like handling interrupts, background activities, and other kernel-related tasks. Attackers may attempt to evade detection by masquerading as a kernel worker process.

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110

Potential Linux Backdoor User Account Creation

Identifies the attempt to create a new backdoor user by setting the user’s UID to 0. Attackers may alter a user’s UID to 0 to establish persistence on a system.

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113

Linux Group Creation

Identifies attempts to create a new group. Attackers may create new groups to establish persistence on a system.

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10

Suspicious Child Execution via Web Server

Identifies suspicious child processes executed via a web server, which may suggest a vulnerability and remote shell access. Attackers may exploit a vulnerability in a web application to execute commands via a web server, or place a backdoor file that can be abused to gain code execution as a mechanism for persistence.

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112

Linux User Account Creation

Identifies attempts to create new users. Attackers may add new users to establish persistence on a system.

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10

Linux User Added to Privileged Group

Identifies attempts to add a user to a privileged group. Attackers may add users to a privileged group in order to establish persistence on a system.

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113

Loadable Kernel Module Configuration File Creation

This rule detects the creation of Loadable Kernel Module (LKM) configuration files. Attackers may create or modify these files to allow their LKMs to be loaded upon reboot, ensuring persistence on a compromised system.

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6

Manual Dracut Execution

This rule detects manual execution of the "dracut" command on Linux systems. Dracut is a tool used to generate an initramfs image that is used to boot the system. Attackers may use "dracut" to create a custom initramfs image that includes malicious code or backdoors, allowing them to maintain persistence on the system.

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6

Message-of-the-Day (MOTD) File Creation

This rule detects the creation of potentially malicious files within the default MOTD file directories. Message of the day (MOTD) is the message that is presented to the user when a user connects to a Linux server via SSH or a serial connection. Linux systems contain several default MOTD files located in the "/etc/update-motd.d/" directory. These scripts run as the root user every time a user connects over SSH or a serial connection. Adversaries may create malicious MOTD files that grant them persistence onto the target every time a user connects to the system by executing a backdoor script or command.

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16

Process Spawned from Message-of-the-Day (MOTD)

Message of the day (MOTD) is the message that is presented to the user when a user connects to a Linux server via SSH or a serial connection. Linux systems contain several default MOTD files located in the "/etc/update-motd.d/" directory. These scripts run as the root user every time a user connects over SSH or a serial connection. Adversaries may create malicious MOTD files that grant them persistence onto the target every time a user connects to the system by executing a backdoor script or command. This rule detects the execution of potentially malicious processes through the MOTD utility.

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114

NetworkManager Dispatcher Script Creation

This rule detects the creation of a NetworkManager dispatcher script on a Linux system. NetworkManager dispatcher scripts are shell scripts that NetworkManager executes when network interfaces change state. Attackers can abuse NetworkManager dispatcher scripts to maintain persistence on a system by executing malicious code whenever a network event occurs.

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5

OpenSSL Password Hash Generation

This rule detects the usage of the "openssl" binary to generate password hashes on Linux systems. The "openssl" command is a cryptographic utility that can be used to generate password hashes. Attackers may use "openssl" to generate password hashes for new user accounts or to change the password of existing accounts, which can be leveraged to maintain persistence on a Linux system.

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5

Pluggable Authentication Module or Configuration Creation

This rule monitors for the creation of Pluggable Authentication Module (PAM) shared object files or configuration files. Attackers may create these files to maintain persistence on a compromised system, or harvest account credentials.

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8

Pluggable Authentication Module (PAM) Creation in Unusual Directory

This rule detects the creation of Pluggable Authentication Module (PAM) shared object files in unusual directories. Attackers may compile PAM shared object files in temporary directories, to move them to system directories later, potentially allowing them to maintain persistence on a compromised system, or harvest account credentials.

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105

Potential Backdoor Execution Through PAM_EXEC

This rule detects SSH session ID change followed by a suspicious SSHD child process, this may indicate the successful execution of a potentially malicious process through the Pluggable Authentication Module (PAM) utility. PAM is a framework used by Linux systems to authenticate users. Adversaries may create malicious PAM modules that grant them persistence onto the target every time a user logs in by executing a backdoor script or command.

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3

Pluggable Authentication Module (PAM) Source Download

This rule detects the usage of "curl" or "wget" to download the source code of a Pluggable Authentication Module (PAM) shared object file. Attackers may download the source code of a PAM shared object file to create a backdoor in the authentication process.

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6

Polkit Policy Creation

This rule monitors for the creation of Polkit policy files on Linux systems. Polkit policy files are used to define the permissions for system-wide services and applications. The creation of new Polkit policy files may indicate an attempt to modify the authentication process, which could be used for persistence by an adversary.

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106

Executable Bit Set for Potential Persistence Script

This rule monitors for the addition of an executable bit for scripts that are located in directories which are commonly abused for persistence. An alert of this rule is an indicator that a persistence mechanism is being set up within your environment. Adversaries may create these scripts to execute malicious code at start-up, or at a set interval to gain persistence onto the system.

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108

Process Capability Set via setcap Utility

This rule detects the use of the setcap utility to set capabilities on a process. The setcap utility is used to set the capabilities of a binary to allow it to perform privileged operations without needing to run as root. This can be used by attackers to establish persistence by creating a backdoor, or escalate privileges by abusing a misconfiguration on a system.

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105

Python Path File (pth) Creation

This rule detects the creation of .pth files in system-wide and user-specific Python package directories, which can be abused for persistent code execution. .pth files automatically execute Python code when the interpreter starts, making them a stealthy persistence mechanism. Monitoring these paths helps identify unauthorized modifications that could indicate persistence by an attacker or malicious package injection.

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5

Suspicious rc.local Error Message

This rule monitors the syslog log file for error messages related to the rc.local process. The rc.local file is a script that is executed during the boot process on Linux systems. Attackers may attempt to modify the rc.local file to execute malicious commands or scripts during system startup. This rule detects error messages such as "Connection refused," "No such file or directory," or "command not found" in the syslog log file, which may indicate that the rc.local file has been tampered with.

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6

Potential Execution of rc.local Script

This rule detects the potential execution of the "/etc/rc.local" script through the "already_running" event action created by the "rc-local.service" systemd service. The "/etc/rc.local" script is a legacy initialization script that is executed at the end of the boot process. The "/etc/rc.local" script is not enabled by default on most Linux distributions. The "/etc/rc.local" script can be used by attackers to persistently execute malicious commands or scripts on a compromised system at reboot. As the rc.local file is executed prior to the initialization of Elastic Defend, the execution event is not ingested, and therefore the "already_running" event is leveraged to provide insight into the potential execution of "rc.local".

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6

rc.local/rc.common File Creation

This rule monitors the creation of the rc.local/rc.common files. The "/etc/rc.local" file is used to start custom applications, services, scripts or commands during start-up. The rc.local file has mostly been replaced by Systemd. However, through the "systemd-rc-local-generator", rc.local files can be converted to services that run at boot. Adversaries may alter rc.local/rc.common to execute malicious code at start-up, and gain persistence onto the system.

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119

RPM Package Installed by Unusual Parent Process

This rule leverages the new_terms rule type to identify the installation of RPM packages by an unusual parent process. RPM is a package management system used in Linux systems such as Red Hat, CentOS and Fedora. Attacks may backdoor RPM packages to gain initial access or install malicious RPM packages to maintain persistence.

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6

Setcap setuid/setgid Capability Set

This rule monitors for the addition of the cap_setuid+ep or cap_setgid+ep capabilities via setcap. Setuid (Set User ID) and setgid (Set Group ID) are Unix-like OS features that enable processes to run with elevated privileges, based on the file owner or group. Threat actors can exploit these attributes to achieve persistence by creating malicious binaries, allowing them to maintain control over a compromised system with elevated permissions.

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111

Shadow File Modification by Unusual Process

This rule monitors for Linux Shadow file modifications. These modifications are indicative of a potential password change or user addition event. Threat actors may attempt to create new users or change the password of a user account to maintain access to a system.

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6

Shared Object Created by Previously Unknown Process

This rule monitors the creation of shared object files by previously unknown processes. The creation of a shared object file involves compiling code into a dynamically linked library that can be loaded by other programs at runtime. While this process is typically used for legitimate purposes, malicious actors can leverage shared object files to execute unauthorized code, inject malicious functionality into legitimate processes, or bypass security controls. This allows malware to persist on the system, evade detection, and potentially compromise the integrity and confidentiality of the affected system and its data.

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14

Shell Configuration Creation

This rule monitors the creation of a shell configuration file. Unix systems use shell configuration files to set environment variables, create aliases, and customize the user’s environment. Adversaries may modify or add a shell configuration file to execute malicious code and gain persistence in the system.

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10

Simple HTTP Web Server Connection

This rule detects connections accepted by a simple HTTP web server in Python and PHP built-in modules. Adversaries may create simple HTTP web servers to establish persistence on a compromised system by uploading a reverse or command shell payload to the server web root, allowing them to regain remote access to the system if lost. This event may occur when an attacker requests the server to execute a command or script via a potential backdoor.

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6

Simple HTTP Web Server Creation

This rule detects the creation of a simple HTTP web server using PHP or Python built-in modules. Adversaries may create simple HTTP web servers to establish persistence on a compromised system by uploading a reverse or command shell payload to the server web root, allowing them to regain remote access to the system if lost.

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105

Python Site or User Customize File Creation

This rule detects the creation and modification of sitecustomize.py and usercustomize.py, which Python automatically executes on startup. Attackers can exploit these files for persistence by injecting malicious code. The rule monitors system-wide, user-specific, and virtual environment locations to catch unauthorized changes that could indicate persistence or backdooring attempts.

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5

Network Connection Initiated by Suspicious SSHD Child Process

This rule identifies an egress internet connection initiated by an SSH Daemon child process. This behavior is indicative of the alteration of a shell configuration file or other mechanism that launches a process when a new SSH login occurs. Attackers can also backdoor the SSH daemon to allow for persistence, call out to a C2 or to steal credentials.

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8

Unusual Login via System User

This rule identifies successful logins by system users that are uncommon to authenticate. These users have "nologin" set by default, and must be modified to allow SSH access. Adversaries may backdoor these users to gain unauthorized access to the system.

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5

Potential Execution via SSH Backdoor

It identifies potential malicious shell executions through remote SSH and detects cases where the sshd service suddenly terminates soon after successful execution, suggesting suspicious behavior similar to the XZ backdoor.

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10

Systemd Generator Created

This rule detects the creation of a systemd generator file. Generators are small executables executed by systemd at bootup and during configuration reloads. Their main role is to convert non-native configuration and execution parameters into dynamically generated unit files, symlinks, or drop-ins, extending the unit file hierarchy for the service manager. Systemd generators can be used to execute arbitrary code at boot time, which can be leveraged by attackers to maintain persistence on a Linux system.

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7

Suspicious Network Connection via systemd

Detects suspicious network events executed by systemd, potentially indicating persistence through a systemd backdoor. Systemd is a system and service manager for Linux operating systems, used to initialize and manage system processes. Attackers can backdoor systemd for persistence by creating or modifying systemd unit files to execute malicious scripts or commands, or by replacing legitimate systemd binaries with compromised ones, ensuring that their malicious code is automatically executed at system startup or during certain system events.

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8

Systemd Timer Created

Detects the creation of a systemd timer within any of the default systemd timer directories. Systemd timers can be used by an attacker to gain persistence, by scheduling the execution of a command or script. Similarly to cron/at, systemd timers can be set up to execute on boot time, or on a specific point in time, which allows attackers to regain access in case the connection to the infected asset was lost.

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19

Systemd Service Created

This rule detects the creation or renaming of a new Systemd file in all of the common Systemd service locations for both root and regular users. Systemd service files are configuration files in Linux systems used to define and manage system services. Malicious actors can leverage systemd service files to achieve persistence by creating or modifying services to execute malicious commands or payloads during system startup or at a predefined interval by adding a systemd timer. This allows them to maintain unauthorized access, execute additional malicious activities, or evade detection.

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19

Systemd Service Started by Unusual Parent Process

Systemctl is a process used in Linux systems to manage systemd processes through service configuration files. Malicious actors can leverage systemd services to achieve persistence by creating or modifying service files to execute malicious commands or payloads during system startup. This allows them to maintain unauthorized access, execute additional malicious activities, or evade detection.

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7

Systemd Shell Execution During Boot

This rule detects the execution of shell commands by systemd during the boot process on Linux systems. Systemd is a system and service manager for Linux operating systems. Attackers may execute shell commands during the boot process to maintain persistence on the system. This may be a sign of malicious systemd services, initramfs or GRUB bootloader manipulation, or other persistence mechanisms.

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5

Tainted Kernel Module Load

This rule monitors the syslog log file for messages related to instances of a tainted kernel module load. Rootkits often leverage kernel modules as their main defense evasion technique. Detecting tainted kernel module loads is crucial for ensuring system security and integrity, as malicious or unauthorized modules can compromise the kernel and lead to system vulnerabilities or unauthorized access.

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8

Tainted Out-Of-Tree Kernel Module Load

This rule monitors the syslog log file for messages related to instances of a out-of-tree kernel module load, indicating the taining of the kernel. Rootkits often leverage kernel modules as their main defense evasion technique. Detecting tainted kernel module loads is crucial for ensuring system security and integrity, as malicious or unauthorized modules can compromise the kernel and lead to system vulnerabilities or unauthorized access.

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6

Systemd-udevd Rule File Creation

Monitors for the creation of rule files that are used by systemd-udevd to manage device nodes and handle kernel device events in the Linux operating system. Systemd-udevd can be exploited for persistence by adversaries by creating malicious udev rules that trigger on specific events, executing arbitrary commands or payloads whenever a certain device is plugged in or recognized by the system.

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11

Initramfs Unpacking via unmkinitramfs

This rule detects the unpacking of an initramfs image using the "unmkinitramfs" command on Linux systems. The "unmkinitramfs" command is used to extract the contents of an initramfs image, which is used to boot the system. Attackers may use "unmkinitramfs" to unpack an initramfs image and modify its contents to include malicious code or backdoors, allowing them to maintain persistence on the system.

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5

Unusual Exim4 Child Process

This rule detects the execution of unusual commands via a descendant process of exim4. Attackers may use descendant processes of exim4 to evade detection and establish persistence or execute post-exploitation commands on a target system.

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3

Authentication via Unusual PAM Grantor

This rule detects successful authentications via PAM grantors that are not commonly used. This could indicate an attacker is attempting to escalate privileges or maintain persistence on the system by modifying the default PAM configuration.

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5

Unusual SSHD Child Process

This rule detects the creation of an unusual SSHD child process through the usage of the "new_terms" rule type. Attackers may abuse SSH to maintain persistence on a compromised system, or to establish a backdoor for remote access, potentially resulting in an unusual SSHD child process being created.

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6

Linux User Account Credential Modification

This rule detects Linux user account credential modification events where the echo command is used to directly echo a password into the passwd or shadow utilities. This technique is used by malware to automate the process of user account credential modification on Linux systems post-infection.

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4

User or Group Creation/Modification

This rule leverages the "auditd_manager" integration to detect user or group creation or modification events on Linux systems. Threat actors may attempt to create or modify users or groups to establish persistence on the system.

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7

Unusual Process Spawned from Web Server Parent

This rule detects unusual processes spawned from a web server parent process by identifying low frequency counts of process spawning activity. Unusual process spawning activity may indicate an attacker attempting to establish persistence, execute malicious commands, or establish command and control channels on the host system. ESQL rules have limited fields available in its alert documents. Make sure to review the original documents to aid in the investigation of this alert.

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9

Unusual Command Execution from Web Server Parent

This rule detects potential command execution from a web server parent process on a Linux host. Adversaries may attempt to execute commands from a web server parent process to blend in with normal web server activity and evade detection. This behavior is commonly observed in web shell attacks where adversaries exploit web server vulnerabilities to execute arbitrary commands on the host. The detection rule identifies unusual command execution from web server parent processes, which may indicate a compromised host or an ongoing attack. ESQL rules have limited fields available in its alert documents. Make sure to review the original documents to aid in the investigation of this alert.

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9

Uncommon Destination Port Connection by Web Server

This rule identifies unusual destination port network activity originating from a web server process. The rule is designed to detect potential web shell activity or unauthorized communication from a web server process to external systems.

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4

Unusual Web Server Command Execution

This rule leverages the "new_terms" rule type to detect unusual command executions originating from web server processes on Linux systems. Attackers may exploit web servers to maintain persistence on a compromised system, often resulting in atypical command executions. As command execution from web server parent processes is common, the "new_terms" rule type approach helps to identify deviations from normal behavior.

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2

Network Connections Initiated Through XDG Autostart Entry

Detects network connections initiated through Cross-Desktop Group (XDG) autostart entries for GNOME and XFCE-based Linux distributions. XDG Autostart entries can be used to execute arbitrary commands or scripts when a user logs in. This rule helps to identify potential malicious activity where an attacker may have modified XDG autostart scripts to establish persistence on the system.

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8

Yum Package Manager Plugin File Creation

Detects file creation events in the plugin directories for the Yum package manager. In Linux, Yum (Yellowdog Updater, Modified) is a command-line utility used for handling packages on (by default) Fedora-based systems, providing functions for installing, updating, upgrading, and removing software along with managing package repositories. Attackers can backdoor Yum to gain persistence by injecting malicious code into plugins that Yum runs, thereby ensuring continued unauthorized access or control each time Yum is used for package management.

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8

Potential Unauthorized Access via Wildcard Injection Detected

This rule monitors for the execution of the "chown" and "chmod" commands with command line flags that could indicate a wildcard injection attack. Linux wildcard injection is a type of security vulnerability where attackers manipulate commands or input containing wildcards (e.g., *, ?, []) to execute unintended operations or access sensitive data by tricking the system into interpreting the wildcard characters in unexpected ways.

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110

Potential Privilege Escalation via Container Misconfiguration

This rule monitors for the execution of processes that interact with Linux containers through an interactive shell without root permissions. Utilities such as runc and ctr are universal command-line utilities leveraged to interact with containers via root permissions. On systems where the access to these utilities are misconfigured, attackers might be able to create and run a container that mounts the root folder or spawn a privileged container vulnerable to a container escape attack, which might allow them to escalate privileges and gain further access onto the host file system.

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10

Potential CVE-2025-32463 Nsswitch File Creation

Detects suspicious creation of the nsswitch.conf file, outside of the regular /etc/nsswitch.conf path, consistent with attempts to exploit CVE-2025-32463 (the "sudo chroot" privilege escalation), where an attacker tricks sudo into using attacker-controlled NSS files or libraries to gain root.

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2

Potential CVE-2025-41244 vmtoolsd LPE Exploitation Attempt

This rule looks for processes that behave like an attacker trying to exploit a known vulnerability in VMware tools (CVE-2025-41244). The vulnerable behavior involves the VMware tools service or its discovery scripts executing other programs to probe their version strings. An attacker can place a malicious program in a writable location (for example /tmp) and have the tools execute it with elevated privileges, resulting in local privilege escalation. The rule flags launches where vmtoolsd or the service discovery scripts start other child processes.

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2

Potential Privilege Escalation via Linux DAC permissions

Identifies potential privilege escalation exploitation of DAC (Discretionary access control) file permissions. The rule identifies exploitation of DAC checks on sensitive file paths via suspicious processes whose capabilities include CAP_DAC_OVERRIDE (where a process can bypass all read write and execution checks) or CAP_DAC_READ_SEARCH (where a process can read any file or perform any executable permission on the directories).

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7

Potential Docker Escape via Nsenter

This rule identifies a UID change event via "nsenter". The "nsenter" command is used to enter a namespace, which is a way to isolate processes and resources. Attackers can use "nsenter" to escape from a container to the host, which can lead to privilege escalation and lateral movement.

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5

Docker Release File Creation

This rule detects the creation of files named release_agent or notify_on_release, which are commonly associated with the abuse of Linux cgroup release mechanisms. In Docker or containerized environments, this behavior may indicate an attempt to exploit privilege escalation vulnerabilities such as CVE-2022-0492, where attackers use the release_agent feature to execute code on the host from within a container.

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3

Modification of Dynamic Linker Preload Shared Object

Identifies modification of the dynamic linker preload shared object (ld.so.preload). Adversaries may execute malicious payloads by hijacking the dynamic linker used to load libraries.

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213

Deprecated - Potential Privilege Escalation via UID INT_MAX Bug Detected

This rule monitors for the execution of the systemd-run command by a user with a UID that is larger than the maximum allowed UID size (INT_MAX). Some older Linux versions were affected by a bug which allows user accounts with a UID greater than INT_MAX to escalate privileges by spawning a shell through systemd-run.

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11

Kernel Load or Unload via Kexec Detected

This detection rule identifies the usage of kexec, helping to uncover unauthorized kernel replacements and potential compromise of the system’s integrity. Kexec is a Linux feature that enables the loading and execution of a different kernel without going through the typical boot process. Malicious actors can abuse kexec to bypass security measures, escalate privileges, establish persistence or hide their activities by loading a malicious kernel, enabling them to tamper with the system’s trusted state, allowing e.g. a VM Escape.

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112

Mount Launched Inside a Container

This rule detects the use of the mount utility from inside a container. The mount command is used to make a device or file system accessible to the system, and then to connect its root directory to a specified mount point on the local file system. When launched inside a privileged container—​a container deployed with all the capabilities of the host machine-- an attacker can access sensitive host level files which could be used for further privilege escalation and container escapes to the host machine. Any usage of mount inside a running privileged container should be further investigated.

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3

Deprecated - Network Connection via Sudo Binary

Detects network connections initiated by the "sudo" binary. This behavior is uncommon and may occur in instances where reverse shell shellcode is injected into a process run with elevated permissions via "sudo". Attackers may attempt to inject shellcode into processes running as root, to escalate privileges.

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8

Privilege Escalation via SUID/SGID

Identifies instances where a process is executed with user/group ID 0 (root), and a real user/group ID that is not 0. This is indicative of a process that has been granted SUID/SGID permissions, allowing it to run with elevated privileges. Attackers may leverage a misconfiguration for exploitation in order to escalate their privileges to root, or establish a backdoor for persistence.

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110

Potential Privilege Escalation via SUID/SGID Proxy Execution

Detects potential privilege escalation via SUID/SGID proxy execution on Linux systems. Attackers may exploit binaries with the SUID/SGID bit set to execute commands with elevated privileges. This rule identifies instances where a process is executed with root privileges (user ID 0 or group ID 0) while the real user or group ID is non-root, indicating potential misuse of SUID/SGID binaries.

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2

Potential Shell via Wildcard Injection Detected

This rule monitors for the execution of a set of linux binaries, that are potentially vulnerable to wildcard injection, with suspicious command line flags followed by a shell spawn event. Linux wildcard injection is a type of security vulnerability where attackers manipulate commands or input containing wildcards (e.g., *, ?, []) to execute unintended operations or access sensitive data by tricking the system into interpreting the wildcard characters in unexpected ways.

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112

Potential Shadow File Read via Command Line Utilities

Identifies access to the /etc/shadow file via the commandline using standard system utilities. After elevating privileges to root, threat actors may attempt to read or dump this file in order to gain valid credentials. They may utilize these to move laterally undetected and access additional resources.

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213

Potential Sudo Privilege Escalation via CVE-2019-14287

This rule monitors for the execution of a suspicious sudo command that is leveraged in CVE-2019-14287 to escalate privileges to root. Sudo does not verify the presence of the designated user ID and proceeds to execute using a user ID that can be chosen arbitrarily. By using the sudo privileges, the command "sudo -u#-1" translates to an ID of 0, representing the root user. This exploit may work for sudo versions prior to v1.28.

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109

Potential Sudo Hijacking

Identifies the creation of a sudo binary located at /usr/bin/sudo. Attackers may hijack the default sudo binary and replace it with a custom binary or script that can read the user’s password in clear text to escalate privileges or enable persistence onto the system every time the sudo binary is executed.

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111

Potential Privilege Escalation via Python cap_setuid

This detection rule monitors for the execution of a system command with setuid or setgid capabilities via Python, followed by a uid or gid change to the root user. This sequence of events may indicate successful privilege escalation. Setuid (Set User ID) and setgid (Set Group ID) are Unix-like OS features that enable processes to run with elevated privileges, based on the file owner or group. Threat actors can exploit these attributes to escalate privileges to the privileges that are set on the binary that is being executed.

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8

Privilege Escalation via CAP_SETUID/SETGID Capabilities

Identifies instances where a process (granted CAP_SETUID and/or CAP_SETGID capabilities) is executed, after which the user’s access is elevated to UID/GID 0 (root). In Linux, the CAP_SETUID and CAP_SETGID capabilities allow a process to change its UID and GID, respectively, providing control over user and group identity management. Attackers may leverage a misconfiguration for exploitation in order to escalate their privileges to root.

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9

Potential Privilege Escalation via Recently Compiled Executable

This rule monitors a sequence involving a program compilation event followed by its execution and a subsequent alteration of UID permissions to root privileges. This behavior can potentially indicate the execution of a kernel or software privilege escalation exploit.

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9

UID Elevation from Previously Unknown Executable

Monitors for the elevation of regular user permissions to root permissions through a previously unknown executable. Attackers may attempt to evade detection by hijacking the execution flow and hooking certain functions/syscalls through a rootkit in order to provide easy access to root via a special modified command.

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8

Namespace Manipulation Using Unshare

Identifies suspicious usage of unshare to manipulate system namespaces. Unshare can be utilized to escalate privileges or escape container security boundaries. Threat actors have utilized this binary to allow themselves to escape to the host and access other resources or escalate privileges.

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114

Potential Network Scan Detected

This rule identifies a potential port scan from an internal IP address. A port scan is a method utilized by attackers to systematically scan a target system for open ports, allowing them to identify available services and potential vulnerabilities. By mapping out the open ports, attackers can gather critical information to plan and execute targeted attacks, gaining unauthorized access, compromising security, and potentially leading to data breaches, unauthorized control, or further exploitation of the targeted system. This rule defines a threshold-based approach to detect connection attempts from a single internal source to a wide range of destination ports on a single destination.

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14

SMB (Windows File Sharing) Activity to the Internet

This rule detects network events that may indicate the use of Windows file sharing (also called SMB or CIFS) traffic to the Internet. SMB is commonly used within networks to share files, printers, and other system resources amongst trusted systems. It should almost never be directly exposed to the Internet, as it is frequently targeted and exploited by threat actors as an initial access or backdoor vector or for data exfiltration.

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108

Connection to Commonly Abused Web Services

Adversaries may implement command and control (C2) communications that use common web services to hide their activity. This attack technique is typically targeted at an organization and uses web services common to the victim network, which allows the adversary to blend into legitimate traffic activity. These popular services are typically targeted since they have most likely been used before compromise, which helps malicious traffic blend in.

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125

Privileged Account Brute Force

Identifies multiple consecutive logon failures targeting an Admin account from the same source address and within a short time interval. Adversaries will often brute force login attempts across multiple users with a common or known password, in an attempt to gain access to accounts.

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117

Multiple Logon Failure from the same Source Address

Identifies multiple consecutive logon failures from the same source address and within a short time interval. Adversaries will often brute force login attempts across multiple users with a common or known password, in an attempt to gain access to accounts.

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117

Potential Computer Account NTLM Relay Activity

Identifies potential relay activities against a Computer account by identifying authentication events using the computer account coming from from hosts other than the server that owns the account. Attackers may relay the computer account hash after capturing it using forced authentication.

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109

LSASS Process Access via Windows API

Identifies access attempts to the LSASS handle, which may indicate an attempt to dump credentials from LSASS memory.

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15

Suspicious Communication App Child Process

Identifies suspicious child processes of communications apps, which can indicate a potential masquerading as the communication app or the exploitation of a vulnerability on the application causing it to execute code.

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12

Command Execution via ForFiles

Detects attempts to execute a command via the forfiles Windows utility. Adversaries may use this utility to proxy execution via a trusted parent process.

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5

Potential Masquerading as Business App Installer

Identifies executables with names resembling legitimate business applications but lacking signatures from the original developer. Attackers may trick users into downloading malicious executables that masquerade as legitimate applications via malicious ads, forum posts, and tutorials, effectively gaining initial access.

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10

Potential Masquerading as Communication Apps

Identifies suspicious instances of communications apps, both unsigned and renamed ones, that can indicate an attempt to conceal malicious activity, bypass security features such as allowlists, or trick users into executing malware.

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12

Potential PowerShell Obfuscation via Invalid Escape Sequences

Identifies PowerShell scripts that use invalid escape sequences as a form of obfuscation. This technique introduces backticks (`) between characters in a way that does not correspond to valid PowerShell escape sequences, breaking up strings and bypassing pattern-based detections while preserving execution logic. This is designed to evade static analysis and bypass security protections such as the Antimalware Scan Interface (AMSI).

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9

Potential PowerShell Obfuscation via Backtick-Escaped Variable Expansion

Identifies PowerShell scripts that use backtick-escaped characters inside ${} variable expansion as a form of obfuscation. These methods are designed to evade static analysis and bypass security protections such as the Antimalware Scan Interface (AMSI).

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7

Potential PowerShell Obfuscation via Character Array Reconstruction

Identifies PowerShell scripts that use character arrays and runtime string reconstruction as a form of obfuscation. This technique breaks strings into individual characters, often using constructs like char[] with index-based access or joining logic. These methods are designed to evade static analysis and bypass security protections such as the Antimalware Scan Interface (AMSI).

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7

Potential PowerShell Obfuscation via Concatenated Dynamic Command Invocation

Identifies PowerShell scripts that use concatenated strings within dynamic command invocation (&() or .()) as a form of obfuscation. These methods are designed to evade static analysis and bypass security protections such as the Antimalware Scan Interface (AMSI).

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7

Potential PowerShell Obfuscation via High Numeric Character Proportion

Identifies PowerShell scripts with a disproportionately high number of numeric characters, often indicating the presence of obfuscated or encoded payloads. This behavior is typical of obfuscation methods involving byte arrays, character code manipulation, or embedded encoded strings used to deliver and execute malicious content.

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9

Potential Dynamic IEX Reconstruction via Environment Variables

Identifies PowerShell scripts that reconstruct the IEX (Invoke-Expression) command at runtime using indexed slices of environment variables. This technique leverages character access and join operations to build execution logic dynamically, bypassing static keyword detection and evading defenses such as AMSI.

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8

Dynamic IEX Reconstruction via Method String Access

Identifies PowerShell scripts that reconstruct the IEX (Invoke-Expression) command by accessing and indexing the string representation of method references. This obfuscation technique uses constructs like ''.IndexOf.ToString() to expose method metadata as a string, then extracts specific characters through indexed access and joins them to form IEX, bypassing static keyword detection and evading defenses such as AMSI.

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9

PowerShell Obfuscation via Negative Index String Reversal

Identifies PowerShell scripts that use negative index ranges to reverse the contents of a string or array at runtime as a form of obfuscation. This technique avoids direct use of reversal functions by iterating through array elements in reverse order. These methods are designed to evade static analysis and bypass security protections such as the Antimalware Scan Interface (AMSI).

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7

Potential PowerShell Obfuscation via Reverse Keywords

Identifies PowerShell scripts that use reversed strings as a form of obfuscation. These methods are designed to evade static analysis and bypass security protections such as the Antimalware Scan Interface (AMSI).

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8

Potential PowerShell Obfuscation via String Concatenation

Identifies PowerShell scripts that use string concatenation as a form of obfuscation. These methods are designed to evade static analysis and bypass security protections such as the Antimalware Scan Interface (AMSI).

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8

Potential PowerShell Obfuscation via String Reordering

Identifies PowerShell scripts that use string reordering and runtime reconstruction techniques as a form of obfuscation. These methods are designed to evade static analysis and bypass security protections such as the Antimalware Scan Interface (AMSI).

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10

Potential PowerShell Obfuscation via Special Character Overuse

Identifies PowerShell scripts with an unusually high proportion of whitespace and special characters, often indicative of obfuscation. This behavior is commonly associated with techniques such as SecureString encoding, formatting obfuscation, or character-level manipulation designed to bypass static analysis and AMSI inspection.

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8

Deprecated - Process Termination followed by Deletion

Identifies a process termination event quickly followed by the deletion of its executable file. Malware tools and other non-native files dropped or created on a system by an adversary may leave traces to indicate to what occurred. Removal of these files can occur during an intrusion, or as part of a post-intrusion process to minimize the adversary’s footprint.

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114

Renamed Utility Executed with Short Program Name

Identifies the execution of a process with a single character process name, differing from the original file name. This is often done by adversaries while staging, executing temporary utilities, or trying to bypass security detections based on the process name.

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216

Suspicious Kerberos Authentication Ticket Request

Correlates network connections to the standard Kerberos port by an unusual process from the source machine with a Kerberos authentication ticket request from the target domain controller.

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3

Remote File Copy to a Hidden Share

Identifies a remote file copy attempt to a hidden network share. This may indicate lateral movement or data staging activity.

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317

Suspicious Service was Installed in the System

Identifies the creation of a new Windows service with suspicious Service command values. Windows services typically run as SYSTEM and can be used for privilege escalation and persistence.

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116

Suspicious Execution via Scheduled Task

Identifies execution of a suspicious program via scheduled tasks by looking at process lineage and command line usage.

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215

Web Shell Detection: Script Process Child of Common Web Processes

Identifies suspicious commands executed via a web server, which may suggest a vulnerability and remote shell access.

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421

Suspicious DLL Loaded for Persistence or Privilege Escalation

Identifies the loading of a non Microsoft signed DLL that is missing on a default Windows install (phantom DLL) or one that can be loaded from a different location by a native Windows process. This may be abused to persist or elevate privileges via privileged file write vulnerabilities.

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219

Process Created with an Elevated Token

Identifies the creation of a process running as SYSTEM and impersonating a Windows core binary privileges. Adversaries may create a new process with a different token to escalate privileges and bypass access controls.

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10