Malicious SSH authorized_keys Modification Following Web Server Compromise (via process_creation)

PremiumReviewedSigma · Medium · v1
Product
linux
Category
process_creation
Author
HuntRule
Published
2026-07-11
Updated
2026-08-28

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 modification of an SSH authorized_keys file through shell commands that append or fetch key material, a persistence technique used after CVE-2025-55182 exploitation to plant attacker SSH keys on compromised servers. Adversaries add their own keys to guarantee durable remote access independent of the web application, so writes to authorized_keys from an exploited host warrant investigation.

Related detections5 linkedT1098.004 — drag to rearrange
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)
Suspicious Modification of SSH Authorized Keys on SD-WAN Appliance by UAT-8616
Malicious Immutable Flag on SSH authorized_keys via chattr
Malicious SSH authorized_keys Modification Following Web Server Compromise (via process_creation)
Pivot detection · T1098.004 · 5 related

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