Obfuscated Base64 Batch Decoding via Certutil in Azorult Infection Chain (via process_creation)

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1027Obfuscated Files or Information
- T1140Deobfuscate/Decode Files or Information
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects certutil.exe decoding a base64 payload into a batch file, the staging behavior used by an Azorult campaign where an LNK writes a base64 blob that certutil decodes and overwrites as a batch script. Using certutil to decode content directly into an executable batch file is a strong defense-evasion and deobfuscation signal rather than routine certificate handling.

Reporting behind it

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Obfuscated Base64 Batch Decoding via Certutil in Azorult Infection Chain (via process_creation)

Pivot detection · T1140 · 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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