T1551.002.md

T1551.002 - Clear Linux or Mac System Logs

Description from ATT&CK

Adversaries may clear system logs to hide evidence of an intrusion. macOS and Linux both keep track of system or user-initiated actions via system logs. The majority of native system logging is stored under the /var/log/ directory. Subfolders in this directory categorize logs by their related functions, such as:(Citation: Linux Logs)

• /var/log/messages:: General and system-related messages
• /var/log/secure or /var/log/auth.log: Authentication logs
• /var/log/utmp or /var/log/wtmp: Login records
• /var/log/kern.log: Kernel logs
• /var/log/cron.log: Crond logs
• /var/log/maillog: Mail server logs
• /var/log/httpd/: Web server access and error logs

Atomic Tests

• Atomic Test #1 - rm -rf

• Atomic Test #2 - Overwrite Linux Mail Spool

• Atomic Test #3 - Overwrite Linux Log

Atomic Test #1 - rm -rf

Delete system and audit logs

Supported Platforms: macOS, Linux

Attack Commands: Run with sh! Elevation Required (e.g. root or admin)

sudo rm -rf /private/var/log/system.log*
sudo rm -rf /private/var/audit/*

Atomic Test #2 - Overwrite Linux Mail Spool

This test overwrites the Linux mail spool of a specified user. This technique was used by threat actor Rocke during the exploitation of Linux web servers.

Supported Platforms: Linux

Inputs:

Name	Description	Type	Default Value
username	Username of mail spool	String	root

Attack Commands: Run with bash!

echo 0> /var/spool/mail/#{username}

Atomic Test #3 - Overwrite Linux Log

This test overwrites the specified log. This technique was used by threat actor Rocke during the exploitation of Linux web servers.

Supported Platforms: Linux

Inputs:

Name	Description	Type	Default Value
log_path	Path of specified log	Path	/var/log/secure

Attack Commands: Run with bash!

echo 0> #{log_path}