Suspicious SSH Authorized Keys Modification via Scripting Interpreter on Linux via Process Creation (via process_creation)

PremiumReviewedSigma · Medium · v1
Product
linux
Category
process_creation
Author
HuntRule
Published
2026-10-23
Updated
2026-10-23

ATT&CK techniques

Persistence → Priv Esc
  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Defense Evasion

  6. Cred Access

  7. Discovery

  8. Lateral Movement

  9. Collection

  10. C2

  11. Exfiltration

  12. Impact

What it detects

This rule detects a scripting interpreter or shell writing to an SSH authorized_keys file, the account-manipulation persistence technique Red Canary demonstrates using perl in its Linux detection guide. Injecting an attacker-controlled public key grants passwordless SSH access that survives reboots, so unexpected modification of authorized_keys is a strong persistence signal.

Related detections9 linkedT1098.004 — drag to rearrange
Malicious SSH authorized_keys Overwrite With Outlaw Marker
Malicious SSH authorized_keys Modification for Persistence on Appliance
Malicious vmanage-admin Public Key Authentication in SSH Auth Log
Suspicious SSH authorized_keys Modification for Persistence
Malicious Immutable Attribute Set on SSH Authorized Keys via chattr on Linux
Suspicious SSH authorized_keys Persistence Modification (via process_creation)
Malicious EtherRAT SSH authorized_keys Backdoor Injection via Shell (via process_creation)
Malicious UNC4841 SSH Backdoor Persistence via Non-Standard Port and AllowUsers Restriction (via process_creation)
Malicious SSH authorized_keys Modification Following Web Server Compromise (via process_creation)
Suspicious SSH Authorized Keys Modification via Scripting Interpreter on Linux via Process Creation (via process_creation)
Pivot detection · T1098.004 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.