Malicious SSH authorized_keys Overwrite With Outlaw Marker

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 shell activity that writes the attacker marker mdrfckr into an SSH authorized_keys file which the Outlaw botnet uses to plant its own key and lock out other access. This grants durable remote access to the compromised Linux host for the mining operation. The hardcoded comment string alongside authorized_keys manipulation is a strong Outlaw indicator.

Reporting behind it

Related detections9 linkedT1098.004 — drag to rearrange

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Suspicious SSH authorized_keys Modification for Persistence

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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 SSH authorized_keys Overwrite With Outlaw Marker

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.

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