Malicious EtherRAT SSH authorized_keys Backdoor Injection via Shell (via process_creation)

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 injection of an SSH public key carrying the root@vps identifier into an authorized_keys file on Linux hosts. This activity is performed by the EtherRAT React2Shell implant to establish persistent root access over SSH. Writing an attacker controlled key into authorized_keys grants durable remote access and should be treated as a compromise.

Reporting behind it

Related detections9 linkedT1098.004 — drag to rearrange

Suspicious SSH Daemon Configuration Change Enabling Root Login

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

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 UNC4841 SSH Backdoor Persistence via Non-Standard Port and AllowUsers Restriction (via process_creation)

Malicious EtherRAT SSH authorized_keys Backdoor Injection via Shell (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.

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