Network Connection from Binary with RWX Memory Regionedit
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.
Rule type: eql
Rule indices:
- logs-endpoint.events.*
- auditbeat-*
- logs-auditd_manager.auditd-*
Severity: medium
Risk score: 47
Runs every: 5m
Searches indices from: now-9m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
References:
Tags:
- Domain: Endpoint
- OS: Linux
- Use Case: Threat Detection
- Tactic: Execution
- Data Source: Elastic Defend
- Data Source: Auditd Manager
Version: 1
Rule authors:
- Elastic
Rule license: Elastic License v2
Setupedit
Setup
This rule requires the use of the auditd_manager integration. Auditd_manager is a tool designed to simplify and enhance the management of the audit subsystem in Linux systems. It provides a user-friendly interface and automation capabilities for configuring and monitoring system auditing through the auditd daemon. With auditd_manager, administrators can easily define audit rules, track system events, and generate comprehensive audit reports, improving overall security and compliance in the system. The following steps should be executed in order to install and deploy auditd_manager on a Linux system.
Kibana --> Management --> Integrations --> Auditd Manager --> Add Auditd Manager
Auditd_manager subscribes to the kernel and receives events as they occur without any additional configuration. However, if more advanced configuration is required to detect specific behavior, audit rules can be added to the integration in either the "audit rules" configuration box or the "auditd rule files" box by specifying a file to read the audit rules from.
For this detection rule to trigger, the following additional audit rules are required to be added to the integration:
-a always,exit -F arch=b64 -S mprotect
Add the newly installed auditd manager to an agent policy, and deploy the agent on a Linux system from which auditd log files are desirable.
Rule queryedit
sample by host.id, process.pid, process.name /* auditd.data.a2 == "7" translates to RWX memory region protection (PROT_READ | PROT_WRITE | PROT_EXEC) */ [process where host.os.type == "linux" and auditd.data.syscall == "mprotect" and auditd.data.a2 == "7"] [network where host.os.type == "linux" and event.type == "start" and event.action == "connection_attempted" and not cidrmatch(destination.ip, "127.0.0.0/8", "169.254.0.0/16", "224.0.0.0/4", "::1")]
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Execution
- ID: TA0002
- Reference URL: https://attack.mitre.org/tactics/TA0002/
-
Technique:
- Name: Command and Scripting Interpreter
- ID: T1059
- Reference URL: https://attack.mitre.org/techniques/T1059/
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Sub-technique:
- Name: Unix Shell
- ID: T1059.004
- Reference URL: https://attack.mitre.org/techniques/T1059/004/
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Tactic:
- Name: Command and Control
- ID: TA0011
- Reference URL: https://attack.mitre.org/tactics/TA0011/
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Technique:
- Name: Application Layer Protocol
- ID: T1071
- Reference URL: https://attack.mitre.org/techniques/T1071/