Suspicious Msiexec Execution with Undocumented -z Flag Proxying DLL (via process_creation)
- Product
- windows
- Category
- process_creation
- Author
- HuntRule
- Published
- 2026-05-29
- Updated
- 2026-08-28
ATT&CK techniques
Defense EvasionRecon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact
What it detects
This rule detects msiexec invoked with the undocumented -z switch, which forces execution of the DllUnregisterServer export of a bundled library. Matanbuchus and DarkGate loaders abused this to proxy malicious DLL execution through a trusted signed binary.
Reporting behind it
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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