Suspicious File Download via certutil urlcache split

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 downloading a file using the urlcache split -f flag combination, an ingress technique used in the ActiveMQ intrusion. Legitimate certutil usage does not combine these download flags, so this pattern reliably flags living-off-the-land payload retrieval.

Reporting behind it

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Suspicious File Download via certutil urlcache split

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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