T1562.012 Disable or Modify Linux Audit System

T1562.012 Disable or Modify Linux Audit System

Sub-technique of: T1562

High-Level Description

Adversaries may disable or modify the Linux audit system to hide malicious activity and avoid detection. Linux admins use the Linux Audit system to track security-relevant information on a system. The Linux Audit system operates at the kernel-level and maintains event logs on application and system activity such as process, network, file, and login events based on pre-configured rules.

Often referred to as auditd, this is the name of the daemon used to write events to disk and is governed by the parameters set in the audit.conf configuration file. Two primary ways to configure the log generation rules are through the command line auditctl utility and the file /etc/audit/audit.rules, containing a sequence of auditctl commands loaded at boot time.

With root privileges, adversaries may be able to ensure their activity is not logged through disabling the Audit system service, editing the configuration/rule files, or by hooking the Audit system library functions. Using the command line, adversaries can disable the Audit system service through killing processes associated with auditd daemon or use systemctl to stop the Audit service. Adversaries can also hook Audit system functions to disable logging or modify the rules contained in the /etc/audit/audit.rules or audit.conf files to ignore malicious activity.

Kill Chain Phase

• Defense Evasion (TA0005)

Platforms: Linux

What to Check

• Identify if Disable or Modify Linux Audit System technique is applicable to target environment
• Check Linux systems for indicators of Disable or Modify Linux Audit System
• Verify mitigations are bypassed or absent (2 known mitigations)
• Assess detection coverage (1 detection strategies)

How to Test

Atomic Red Team Tests

The following tests are from Atomic Red Team and provide actionable ways to test this technique:

Atomic Test 1: Delete all auditd rules using auditctl

Using 'auditctl -D' deletes all existing audit rules, resulting in the loss of previously configured monitoring settings and the audit trail. This action reduces visibility into system activities, potentially leading to compliance concerns and hampering security monitoring efforts. Additionally, it poses a risk of covering unauthorized activities by erasing evidence from audit logs.

Supported Platforms: linux Elevation Required: Yes

auditctl -D