Suspicious Certutil URLCache Remote Payload Download via process_creation

ATT&CK techniques

C2

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1105Ingress Tool Transfer
Exfiltration
Impact

What it detects

This rule detects certutil.exe invoked with the urlcache and split flags which downloads a remote file to disk while masquerading as certificate maintenance. Attackers in the SOC web shell case used obfuscated certutil to fetch a 404.aspx web shell onto the server. This living-off-the-land download technique bypasses many application allow lists and is worth alerting on.

Reporting behind it

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Suspicious Certutil URLCache Remote Payload Download via process_creation

Pivot detection · T1105 · 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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