Malicious WARMCOOKIE DLL Execution from RtlUpd Path via rundll32

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218.011Rundll32
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects rundll32.exe executing a DLL from the C:\ProgramData\RtlUpd directory, the fixed drop path and loader behavior of the WARMCOOKIE backdoor. The malware writes RtlUpd.dll to this ProgramData location and runs it via rundll32 to establish its foothold.

Reporting behind it

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Suspicious Rundll32 Loading DLL from LocalAppData with Short Export (via process_creation)

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Malicious WARMCOOKIE DLL Execution from RtlUpd Path via rundll32

Pivot detection · T1218.011 · 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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