Malicious Immutable Attribute Set on SSH Authorized Keys via chattr on Linux

ATT&CK techniques

Persistence → Priv Esc

Recon
Resource Dev
Initial Access
Execution
Persistence
- T1098.004SSH Authorized Keys
Priv Esc
- T1098.004SSH Authorized Keys
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects the chattr command applying the append only or immutable attribute to an SSH authorized_keys file which cryptomining actors abusing container APIs use to lock in their backdoor SSH key and prevent defenders or competing miners from removing it.

Reporting behind it

Related detections6 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)

Malicious SSH authorized_keys Modification Following Web Server Compromise (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 Immutable Attribute Set on SSH Authorized Keys via chattr on Linux

Pivot detection · T1098.004 · 6 related

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

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