TA0005 · DEFENSE EVASION
Clear Command History
In addition to clearing system logs, an adversary may clear the command history of a compromised account to conceal the actions undertaken during an intrusion.
Detect it with
User authentication, especially via remote terminal services like SSH, without new entries in that user's ~/.bash_history is suspicious. Additionally, the removal/clearing of the ~/.bash_history file can be an indicator of suspicious activity.
Why it matters on shift
Clear Command History is one of the concrete ways adversaries achieve defense evasion. Recognising it in telemetry lets you name the technique in your ticket and pivot to what came before and after.
What to look for next
After defense evasion, the next tactic is usually Credential Access. Search your telemetry for the transition before closing the ticket.
Kill-chain context