Malicious KB Document Masqueraded Executable Spawned by Script Interpreter via RoKRAT Loader (via process_creation)

ATT&CK techniques

Execution → Defense Evasion

Recon
Resource Dev
Initial Access
Execution
- T1059.003Windows Command Shell
- T1204.002Malicious File
Persistence
Priv Esc
Defense Evasion
- T1027Obfuscated Files or Information
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects execution of an executable named to impersonate a Windows KB update document such as KB400928_doc.exe when launched by cmd.exe or powershell.exe, as seen in the APT37 ToyBox Story cmd to powershell to payload chain delivering RoKRAT. The KB prefix with a _doc.exe suffix masquerades the payload as a benign document while it runs as a program. Catching this masqueraded binary being spawned by a script interpreter exposes the final loader execution stage.

Reporting behind it

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Malicious KB Document Masqueraded Executable Spawned by Script Interpreter via RoKRAT Loader (via process_creation)

Pivot detection · T1059.003 · 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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