TA0003 · PERSISTENCE
SSH Authorized Keys
Adversaries may modify the SSH authorized_keys file to maintain persistence on a victim host. Linux distributions, macOS, and ESXi hypervisors commonly use key-based authentication to secure the authentication process of SSH sessions for remote management.
Detect it with
Use file integrity monitoring to detect changes made to the authorized_keys file for each user on a system. Monitor for suspicious processes modifying the authorized_keys file.
Why it matters on shift
SSH Authorized Keys is one of the concrete ways adversaries achieve persistence. 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 persistence, the next tactic is usually Privilege Escalation. Search your telemetry for the transition before closing the ticket.
Kill-chain context