Malicious APT29 Certutil Decode of Disguised Text File to Archive (via process_creation)

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1140Deobfuscate/Decode Files or Information
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects certutil decoding a .txt file into a .zip archive, the staging step APT29 used to reconstruct a WINELOADER payload from a disguised invite. Delivering the archive as Base64 text and decoding it locally with certutil evades transfer-time inspection. Certutil decoding text into an archive is a deobfuscation behavior tied to this intrusion set.

Reporting behind it

Related detections9 linkedT1140 — drag to rearrange

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Suspicious Hex Decoding Piped to Shell via xxd on macOS

Malicious GitVenom Python Fernet Decrypt-and-Execute Loader via process_creation

Certutil Decoding Encoded Payload to Executable

Malicious APT29 Certutil Decode of Disguised Text File to Archive (via process_creation)

Pivot detection · T1140 · 9 related

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