IMPORTANT: This documentation is no longer updated. Refer to Elastic's version policy and the latest documentation.

Update v8.19.12

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This section lists all updates associated with version 8.19.12 of the Fleet integration Prebuilt Security Detection Rules.

Rule Description Status Version

GenAI Process Connection to Suspicious Top Level Domain

Detects when GenAI tools connect to domains using suspicious TLDs commonly abused for malware C2 infrastructure. TLDs like .top, .xyz, .ml, .cf, .onion are frequently used in phishing and malware campaigns. Legitimate GenAI services use well-established domains (.com, .ai, .io), so connections to suspicious TLDs may indicate compromised tools, malicious plugins, or AI-generated code connecting to attacker infrastructure.

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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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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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Potential Secret Scanning via Gitleaks

This rule detects the execution of Gitleaks, a tool used to search for high-entropy strings and secrets in code repositories, which may indicate an attempt to access credentials.

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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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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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GenAI Process Compiling or Generating Executables

Detects when GenAI tools spawn compilers or packaging tools to generate executables. Attackers leverage local LLMs to autonomously generate and compile malware, droppers, or implants. Python packaging tools (pyinstaller, nuitka, pyarmor) are particularly high-risk as they create standalone executables that can be deployed without dependencies. This rule focuses on compilation activity that produces output binaries, filtering out inspection-only operations.

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GenAI Process Performing Encoding/Chunking Prior to Network Activity

Detects when GenAI processes perform encoding or chunking (base64, gzip, tar, zip) followed by outbound network activity. This sequence indicates data preparation for exfiltration. Attackers encode or compress sensitive data before transmission to obfuscate contents and evade detection. Legitimate GenAI workflows rarely encode data before network communications.

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Potential HTTP Downgrade Attack

Through the new_terms rule type, this rule detects potential HTTP downgrade attacks by identifying HTTP traffic that uses a different HTTP version than the one typically used in the environment. An HTTP downgrade attack occurs when an attacker forces a connection via an older HTTP version, resulting in potentially less secure communication. For example, an attacker might downgrade a connection from HTTP/2 to HTTP/1.1 or HTTP/1.0 to exploit known vulnerabilities or weaknesses in the older protocol versions.

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AWS EC2 LOLBin Execution via SSM SendCommand

Identifies the execution of Living Off the Land Binaries (LOLBins) or GTFOBins on EC2 instances via AWS Systems Manager (SSM) SendCommand API. This detection correlates AWS CloudTrail SendCommand events with endpoint process execution by matching SSM command IDs. While AWS redacts command parameters in CloudTrail logs, this correlation technique reveals the actual commands executed on EC2 instances. Adversaries may abuse SSM to execute malicious commands remotely without requiring SSH or RDP access, using legitimate system utilities for data exfiltration, establishing reverse shells, or lateral movement.

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Privileged Container Creation with Host Directory Mount

This rule detects the creation of privileged containers that mount host directories into the container’s filesystem. Such configurations can be exploited by attackers to escape the container isolation and gain access to the host system, potentially leading to privilege escalation and lateral movement within the environment.

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Remote GitHub Actions Runner Registration

This rule detects the configuration of a GitHub Actions self-hosted runner using the Runner.Listener binary. When a machine is registered to a remote repository, its owner gains the ability to execute arbitrary workflow commands on that host. Unexpected or unauthorized runner registration may indicate adversarial activity aimed at establishing remote code execution via malicious GitHub workflows.

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Execution via GitHub Actions Runner

This rule detects potentially dangerous commands spawned by the GitHub Actions Runner.Worker process on self-hosted runner machines. Adversaries who gain the ability to modify or trigger workflows in a linked GitHub repository can execute arbitrary commands on the runner host. This behavior may indicate malicious or unexpected workflow activity, including code execution, file manipulation, or network exfiltration initiated through a compromised repository or unauthorized workflow.

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Tampering with RUNNER_TRACKING_ID in GitHub Actions Runners

This rule detects processes spawned by GitHub Actions runners where "RUNNER_TRACKING_ID" is overridden from its default "github_*" value. Such tampering has been associated with attempts to evade runner tracking/cleanup on self-hosted runners, including behavior observed in the Shai-Hulud 2.0 npm worm campaign.

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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

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Initial Access via File Upload Followed by GET Request

This rule detects potential initial access activity where an adversary uploads a web shell or malicious script to a web server via a file upload mechanism (e.g., through a web form using multipart/form-data), followed by a GET or POST request to access the uploaded file. By checking the body content of HTTP requests for file upload indicators such as "Content-Disposition: form-data" and "filename=", the rule identifies suspicious upload activities. This sequence of actions is commonly used by attackers to gain and maintain access to compromised web servers.

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Suspicious Microsoft Entra ID Concurrent Sign-Ins via DeviceCode

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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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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Pod or Container Creation with Suspicious Command-Line

This rule detects the creation of pods or containers that execute suspicious commands often associated with persistence or privilege escalation techniques. Attackers may use container orchestration tools like kubectl or container runtimes like docker to create pods or containers that run shell commands with arguments that indicate attempts to establish persistence (e.g., modifying startup scripts, creating backdoors).

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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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React2Shell (CVE-2025-55182) Exploitation Attempt

This rule detects exploitation attempts targeting CVE-2025-55182, 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. This rule focuses on high-fidelity indicators of active exploitation including successful command execution responses and prototype pollution attack patterns.

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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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Credential Access via TruffleHog Execution

This rule detects the execution of TruffleHog, a tool used to search for high-entropy strings and secrets in code repositories, which may indicate an attempt to access credentials. This tool was abused by the Shai-Hulud worm to search for credentials in code repositories.

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Node.js Pre or Post-Install Script Execution

This rule detects the execution of Node.js pre or post-install scripts. These scripts are executed by the Node.js package manager (npm) during the installation of packages. Adversaries may abuse this technique to execute arbitrary commands on the system and establish persistence. This activity was observed in the wild as part of the Shai-Hulud worm.

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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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Deprecated - Modification of Standard Authentication Module or Configuration

Adversaries may modify the standard authentication module for persistence via patching the normal authorization process or modifying the login configuration to allow unauthorized access or elevate privileges.

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Web Server Potential Command Injection Request

This rule detects potential command injection attempts via web server requests by identifying URLs that contain suspicious patterns commonly associated with command execution payloads. Attackers may exploit vulnerabilities in web applications to inject and execute arbitrary commands on the server, often using interpreters like Python, Perl, Ruby, PHP, or shell commands. By monitoring for these indicators in web traffic, security teams can identify and respond to potential threats early.

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Web Server Discovery or Fuzzing Activity

This rule detects potential web server discovery or fuzzing activity by identifying a high volume of HTTP GET requests resulting in 404 or 403 status codes from a single source IP address within a short timeframe. Such patterns may indicate that an attacker is attempting to discover hidden or unlinked resources on a web server, which can be a precursor to more targeted attacks.

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Potential Spike in Web Server Error Logs

This rule detects unusual spikes in error logs from web servers, which may indicate reconnaissance activities such as vulnerability scanning or fuzzing attempts by adversaries. These activities often generate a high volume of error responses as they probe for weaknesses in web applications. Error response codes may potentially indicate server-side issues that could be exploited.

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Web Server Potential Spike in Error Response Codes

This rule detects unusual spikes in error response codes (500, 502, 503, 504) from web servers, which may indicate reconnaissance activities such as vulnerability scanning or fuzzing attempts by adversaries. These activities often generate a high volume of error responses as they probe for weaknesses in web applications. Error response codes may potentially indicate server-side issues that could be exploited.

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Web Server Suspicious User Agent Requests

This rule detects unusual spikes in web server requests with uncommon or suspicious user-agent strings. Such activity may indicate reconnaissance attempts by attackers trying to identify vulnerabilities in web applications or servers. These user-agents are often associated with automated tools used for scanning, vulnerability assessment, or brute-force attacks.

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AWS RDS DB Instance Restored

Identifies the restoration of an AWS RDS database instance from a snapshot or S3 backup. Adversaries with access to valid credentials may restore copies of existing databases to bypass logging and monitoring controls or to exfiltrate sensitive data from a duplicated environment. This rule detects successful restoration operations using "RestoreDBInstanceFromDBSnapshot" or "RestoreDBInstanceFromS3", which may indicate unauthorized data access or post-compromise defense evasion.

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AWS IAM Principal Enumeration via UpdateAssumeRolePolicy

Detects repeated failed attempts to update an IAM role’s trust policy in an AWS account, consistent with role and user enumeration techniques. In this technique, an attacker who controls credentials in the current account repeatedly calls UpdateAssumeRolePolicy on a single role, cycling through guessed cross-account role or user ARNs as the principal. When those principals are invalid, IAM returns MalformedPolicyDocumentException, producing a burst of failed UpdateAssumeRolePolicy events. This rule alerts on that brute-force pattern originating from this account, which may indicate that the account is being used as attack infrastructure or that offensive tooling (such as Pacu) is running here. Note: this rule does not detect other accounts enumerating roles, because those API calls are logged in the caller’s account, not the target account.

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AWS Discovery API Calls via CLI from a Single Resource

Detects when a single AWS resource is running multiple read-only, discovery API calls in a 10-second window. This behavior could indicate an actor attempting to discover the AWS infrastructure using compromised credentials or a compromised instance. Adversaries may use this information to identify potential targets for further exploitation or to gain a better understanding of the target’s infrastructure.

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AWS RDS Snapshot Export

Identifies the export of a DB snapshot or DB cluster data to Amazon S3. Snapshot exports can be used for analytics or migration workflows, but adversaries may abuse them to exfiltrate sensitive data outside of RDS-managed storage. Exporting a snapshot creates a portable copy of the database contents, which, if performed without authorization, can indicate data theft, staging for exfiltration, or operator misconfiguration that exposes regulated information.

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AWS RDS DB Snapshot Shared with Another Account

Identifies when an AWS RDS DB snapshot is shared with another AWS account or made public. DB snapshots contain complete backups of database instances, including schemas, table data, and sensitive application content. When shared externally, snapshots can be restored in another AWS environment, enabling unauthorized access, offline analysis, or data exfiltration. Adversaries who obtain valid credentials or exploit misconfigurations may modify snapshot attributes to grant access to accounts they control, bypassing network, IAM, and monitoring controls.

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AWS S3 Bucket Policy Added to Share with External Account

Detects when an Amazon S3 bucket policy is modified to share access with an external AWS account. This rule analyzes PutBucketPolicy events and compares the S3 bucket’s account ID to any account IDs referenced in the policy’s Effect=Allow statements. If the policy includes principals from accounts other than the bucket owner’s, the rule triggers an alert. This behavior may indicate an adversary backdooring a bucket for data exfiltration or cross-account persistence. For example, an attacker who compromises credentials could attach a policy allowing access from an external AWS account they control, enabling continued access even after credentials are rotated. Note: This rule will not alert if the account ID is part of the bucket’s name or appears in the resource ARN. Such cases are common in standardized naming conventions (e.g., “mybucket-123456789012”). To ensure full coverage, use complementary rules to monitor for suspicious PutBucketPolicy API requests targeting buckets with account IDs embedded in their names or resources.

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AWS S3 Bucket Replicated to Another Account

Identifies the creation or modification of an S3 bucket replication configuration that sends data to a bucket in a different AWS account. Cross-account replication can be used legitimately for backup, disaster recovery, and multi-account architectures, but adversaries with write access to an S3 bucket may abuse replication rules to silently exfiltrate large volumes of data to attacker-controlled accounts. This rule detects "PutBucketReplication" events where the configured destination account differs from the source bucket’s account, indicating potential unauthorized cross-account data movement.

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AWS EFS File System Deleted

Identifies the deletion of an Amazon EFS file system using the "DeleteFileSystem" API operation. Deleting an EFS file system permanently removes all stored data and cannot be reversed. This action is rare in most environments and typically limited to controlled teardown workflows. Adversaries with sufficient permissions may delete a file system to destroy evidence, disrupt workloads, or impede recovery efforts.

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AWS KMS Customer Managed Key Disabled or Scheduled for Deletion

Identifies attempts to disable or schedule the deletion of an AWS customer managed KMS Key. Disabling or scheduling a KMS key for deletion removes the ability to decrypt data encrypted under that key and can permanently destroy access to critical resources. Adversaries may use these operations to cause irreversible data loss, disrupt business operations, impede incident response, or hide evidence of prior activity. Because KMS keys often protect sensitive or regulated data, any modification to their lifecycle should be considered highly sensitive and investigated promptly.

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AWS RDS DB Instance or Cluster Deleted

Identifies the deletion of an Amazon RDS DB instance, Aurora cluster, or global database cluster. Deleting these resources permanently destroys stored data and can cause major service disruption. Adversaries with sufficient permissions may delete RDS resources to impede recovery, destroy evidence, or inflict operational impact on the environment.

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AWS RDS DB Instance or Cluster Deletion Protection Disabled

Identifies the modification of an AWS RDS DB instance or cluster to disable the deletionProtection feature. Deletion protection prevents accidental or unauthorized deletion of RDS resources. Adversaries with sufficient permissions may disable this protection as a precursor to destructive actions, including the deletion of databases containing sensitive or business-critical data. This rule alerts when deletionProtection is explicitly set to false on an RDS DB instance or cluster.

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AWS RDS Snapshot Deleted

Identifies the deletion of an AWS RDS DB snapshot or configuration changes that effectively remove backup coverage for a DB instance. RDS snapshots contain full backups of database instances, and disabling automated backups by setting "backupRetentionPeriod=0" has a similar impact by preventing future restore points. Adversaries with the appropriate permissions may delete snapshots or disable backups to inhibit recovery, destroy forensic evidence, or prepare for follow-on destructive actions such as instance or cluster deletion.

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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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AWS Access Token Used from Multiple Addresses

This rule identifies potentially suspicious activity by detecting instances where a single IAM user’s temporary session token is accessed from multiple IP addresses within a short time frame. Such behavior may suggest that an adversary has compromised temporary credentials and is utilizing them from various locations. To enhance detection accuracy and minimize false positives, the rule incorporates criteria that evaluate unique IP addresses, user agents, cities, and networks. These additional checks help distinguish between legitimate distributed access patterns and potential credential misuse. Detected activities are classified into different types based on the combination of unique indicators, with each classification assigned a fidelity score reflecting the likelihood of malicious behavior. High fidelity scores are given to patterns most indicative of threats, such as multiple unique IPs, networks, cities, and user agents. Medium and low fidelity scores correspond to less severe patterns, enabling security teams to effectively prioritize alerts.

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Spike in AWS Error Messages

A machine learning job detected a significant spike in the rate of a particular error in the CloudTrail messages. Spikes in error messages may accompany attempts at privilege escalation, lateral movement, or discovery.

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Rare AWS Error Code

A machine learning job detected an unusual error in a CloudTrail message. These can be byproducts of attempted or successful persistence, privilege escalation, defense evasion, discovery, lateral movement, or collection.

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Unusual City For an AWS Command

A machine learning job detected AWS command activity that, while not inherently suspicious or abnormal, is sourcing from a geolocation (city) that is unusual for the command. This can be the result of compromised credentials or keys being used by a threat actor in a different geography than the authorized user(s).

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Unusual Country For an AWS Command

A machine learning job detected AWS command activity that, while not inherently suspicious or abnormal, is sourcing from a geolocation (country) that is unusual for the command. This can be the result of compromised credentials or keys being used by a threat actor in a different geography than the authorized user(s).

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Unusual AWS Command for a User

A machine learning job detected an AWS API command that, while not inherently suspicious or abnormal, is being made by a user context that does not normally use the command. This can be the result of compromised credentials or keys as someone uses a valid account to persist, move laterally, or exfiltrate data.

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AWS RDS DB Instance or Cluster Password Modified

Identifies the modification of the master password for an AWS RDS DB instance or cluster. Changing the master password is a legitimate recovery action when access is lost, but adversaries with sufficient permissions may modify it to regain access, establish persistence, bypass existing controls, or escalate privileges within a compromised environment. Because RDS does not expose the password in API responses, this operation can meaningfully alter access pathways to sensitive data stores.

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AWS RDS DB Instance Made Public

Identifies the creation or modification of an Amazon RDS DB instance or cluster where the "publiclyAccessible" attribute is set to "true". Publicly accessible RDS instances expose a network endpoint on the public internet, which may allow unauthorized access if combined with overly permissive security groups, weak authentication, or misconfigured IAM policies. Adversaries may enable public access on an existing instance, or create a new publicly accessible instance, to establish persistence, move data outside of controlled network boundaries, or bypass internal access controls.

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Deprecated - AWS Redshift Cluster Creation

Identifies the creation of an Amazon Redshift cluster. Unexpected creation of this cluster by a non-administrative user may indicate a permission or role issue with current users. If unexpected, the resource may not properly be configured and could introduce security vulnerabilities.

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AWS STS AssumeRoot by Rare User and Member Account

Identifies when the STS AssumeRoot action is performed by a rare user in AWS. The AssumeRoot action allows users to assume the root member account role, granting elevated but specific permissions based on the task policy specified. Adversaries who have compromised user credentials can use this technique to escalate privileges and gain unauthorized access to AWS resources. This is a New Terms rule that identifies when the STS AssumeRoot action is performed by a user that rarely assumes this role against a specific member account.

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Potential Persistence via File Modification

This rule leverages the File Integrity Monitoring (FIM) integration to detect file modifications of files that are commonly used for persistence on Linux systems. The rule detects modifications to files that are commonly used for cron jobs, systemd services, message-of-the-day (MOTD), SSH configurations, shell configurations, runtime control, init daemon, passwd/sudoers/shadow files, Systemd udevd, and XDG/KDE autostart entries. To leverage this rule, the paths specified in the query need to be added to the FIM policy in the Elastic Security app.

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M365 OneDrive Excessive File Downloads with OAuth Token

Identifies when an excessive number of files are downloaded from OneDrive using OAuth authentication. Adversaries may conduct phishing campaigns to steal OAuth tokens and impersonate users. These access tokens can then be used to download files from OneDrive.

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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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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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Creation or Modification of Pluggable Authentication Module or Configuration

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

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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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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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Spike in host-based traffic

A machine learning job has detected a sudden spike in host based traffic. This can be due to a range of security issues, such as a compromised system, DDoS attacks, malware infections, privilege escalation, or data exfiltration.

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Spike in Firewall Denies

A machine learning job detected an unusually large spike in network traffic that was denied by network access control lists (ACLs) or firewall rules. Such a burst of denied traffic is usually caused by either 1) a mis-configured application or firewall or 2) suspicious or malicious activity. Unsuccessful attempts at network transit, in order to connect to command-and-control (C2), or engage in data exfiltration, may produce a burst of failed connections. This could also be due to unusually large amounts of reconnaissance or enumeration traffic. Denial-of-service attacks or traffic floods may also produce such a surge in traffic.

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Spike in Network Traffic

A machine learning job detected an unusually large spike in network traffic. Such a burst of traffic, if not caused by a surge in business activity, can be due to suspicious or malicious activity. Large-scale data exfiltration may produce a burst of network traffic; this could also be due to unusually large amounts of reconnaissance or enumeration traffic. Denial-of-service attacks or traffic floods may also produce such a surge in traffic.

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Unusual Linux Network Activity

Identifies Linux processes that do not usually use the network but have unexpected network activity, which can indicate command-and-control, lateral movement, persistence, or data exfiltration activity. A process with unusual network activity can denote process exploitation or injection, where the process is used to run persistence mechanisms that allow a malicious actor remote access or control of the host, data exfiltration, and execution of unauthorized network applications.

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Unusual Linux Network Port Activity

Identifies unusual destination port activity that can indicate command-and-control, persistence mechanism, or data exfiltration activity. Rarely used destination port activity is generally unusual in Linux fleets, and can indicate unauthorized access or threat actor activity.

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Decline in host-based traffic

A machine learning job has detected a sudden drop in host based traffic. This can be due to a range of security issues, such as a compromised system, a failed service, or a network misconfiguration.

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Unusual Network Destination Domain Name

A machine learning job detected an unusual network destination domain name. This can be due to initial access, persistence, command-and-control, or exfiltration activity. For example, when a user clicks on a link in a phishing email or opens a malicious document, a request may be sent to download and run a payload from an uncommon web server name. When malware is already running, it may send requests to an uncommon DNS domain the malware uses for command-and-control communication.

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Network Traffic to Rare Destination Country

A machine learning job detected a rare destination country name in the network logs. This can be due to initial access, persistence, command-and-control, or exfiltration activity. For example, when a user clicks on a link in a phishing email or opens a malicious document, a request may be sent to download and run a payload from a server in a country which does not normally appear in network traffic or business work-flows. Malware instances and persistence mechanisms may communicate with command-and-control (C2) infrastructure in their country of origin, which may be an unusual destination country for the source network.

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Spike in Network Traffic To a Country

A machine learning job detected an unusually large spike in network activity to one destination country in the network logs. This could be due to unusually large amounts of reconnaissance or enumeration traffic. Data exfiltration activity may also produce such a surge in traffic to a destination country that does not normally appear in network traffic or business workflows. Malware instances and persistence mechanisms may communicate with command-and-control (C2) infrastructure in their country of origin, which may be an unusual destination country for the source network.

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Unusual Windows Network Activity

Identifies Windows processes that do not usually use the network but have unexpected network activity, which can indicate command-and-control, lateral movement, persistence, or data exfiltration activity. A process with unusual network activity can denote process exploitation or injection, where the process is used to run persistence mechanisms that allow a malicious actor remote access or control of the host, data exfiltration, and execution of unauthorized network applications.

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210

External Alerts

Generates a detection alert for each external alert written to the configured indices. Enabling this rule allows you to immediately begin investigating external alerts in the app.

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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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Rare Connection to WebDAV Target

Identifies rare connection attempts to a Web Distributed Authoring and Versioning (WebDAV) resource. Attackers may inject WebDAV paths in files or features opened by a victim user to leak their NTLM credentials via forced authentication.

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5

Potential PowerShell Obfuscated Script

Identifies scripts that contain patterns and known methods that obfuscate PowerShell code. Attackers can use obfuscation techniques to bypass PowerShell security protections such as Antimalware Scan Interface (AMSI).

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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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8

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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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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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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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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8

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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7

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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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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6

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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7

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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7

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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9

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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7

Host File System Changes via Windows Subsystem for Linux

Detects file creation and modification on the host system from the Windows Subsystem for Linux. Adversaries may enable and use WSL to avoid detection.

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112

Potential PowerShell HackTool Script by Function Names

Detects known PowerShell offensive tooling functions names in PowerShell scripts. Attackers commonly use out-of-the-box offensive tools without modifying the code. This rule aim is to take advantage of that.

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219

Suspicious PowerShell Engine ImageLoad

Identifies the PowerShell engine being invoked by unexpected processes. Rather than executing PowerShell functionality with powershell.exe, some attackers do this to operate more stealthily.

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215

Suspicious Windows Powershell Arguments

Identifies the execution of PowerShell with suspicious argument values. This behavior is often observed during malware installation leveraging PowerShell.

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210

Potential System Tampering via File Modification

Identifies attempts to delete or modify critical files used during the boot process to prevent the system from booting. This may indicate a destructive attack behavior.

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3

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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2

Remote Scheduled Task Creation

Identifies remote scheduled task creations on a target host. This could be indicative of adversary lateral movement.

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214

Browser Extension Install

Identifies the install of browser extensions. Malicious browser extensions can be installed via app store downloads masquerading as legitimate extensions, social engineering, or by an adversary that has already compromised a system.

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207

Persistence via a Windows Installer

Identifies when the Windows installer process msiexec.exe creates a new persistence entry via scheduled tasks or startup.

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5

Potential Application Shimming via Sdbinst

The Application Shim was created to allow for backward compatibility of software as the operating system codebase changes over time. This Windows functionality has been abused by attackers to stealthily gain persistence and arbitrary code execution in legitimate Windows processes.

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317

SeDebugPrivilege Enabled by a Suspicious Process

Identifies a process running with a non-SYSTEM account that enables the SeDebugPrivilege privilege. Adversaries may enable this privilege to debug and modify other processes, typically reserved for system-level tasks, to escalate privileges and bypass access controls.

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113

Unusual Print Spooler Child Process

Detects unusual Print Spooler service (spoolsv.exe) child processes. This may indicate an attempt to exploit privilege escalation vulnerabilities related to the Printing Service on Windows.

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215

Privileges Elevation via Parent Process PID Spoofing

Identifies parent process spoofing used to create an elevated child process. Adversaries may spoof the parent process identifier (PPID) of a new process to evade process-monitoring defenses or to elevate privileges.

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11