Malicious BadIIS C2 Communication via lwxatisme User-Agent

ATT&CK techniques

Persistence → C2

Recon
Resource Dev
Initial Access
Execution
Persistence
- T1505.004IIS Components
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1071.001Web Protocols
Exfiltration
Impact

What it detects

This rule detects HTTP traffic carrying the User-Agent string lwxatisme, a fixed marker used by the commodity BadIIS ecosystem tracked by Talos to authenticate to its C2. The BadIIS native IIS module keys off this hardcoded agent to gate operator commands. Presence of this User-Agent indicates a BadIIS-infected server communicating with its controller.

Reporting behind it

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Malicious BadIIS C2 Communication via lwxatisme User-Agent

Pivot detection · T1071.001 · 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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