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Clear or Disable Kernel Ring Buffer Logs via Syslog Syscall

Sigma Rules

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Summary
This rule is designed to detect attempts to clear or disable kernel ring buffer logs on Linux systems through the use of the `syslog` syscall. Specifically, it monitors actions related to action codes 4, 5, and 6 which correspond to reading and clearing the dmesg logs, and disabling kernel logging output respectively. Attackers may employ these techniques to erase traces of their activity post-exploitation or privilege escalation. This rule utilizes the Linux audit daemon (auditd) to log these syscalls and identify potential evasion activities. The detection is triggered when the monitored action codes are invoked, marking potential malicious behavior. It is important to note that legitimate actions by system administrators or debugging processes can also generate similar syscall activity, which are considered false positives.
Categories
  • Linux
  • Endpoint
Data Sources
  • Process
  • Kernel
  • Service
Created: 2025-05-27