huntrule

Windows: Registry Set by Rundll32 for Screen Saver Execution via SCRNSAVE.EXE

Flags Windows registry sets where Rundll32 points SCRNSAVE.EXE to a .scr file.

FreeReviewedSigma · Medium · v1
Product
windows
Category
registry_set
Author
Jose Luis Sanchez Martinez (@Joseliyo_Jstnk) (SigmaHQ), DRL 1.1
Published
2022-05-04
Updated
2026-07-30
AnalysisDetection

ATT&CK techniques

Defense Evasion

  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. C2

  13. Exfiltration

  14. Impact

What it detects

This rule identifies when Rundll32 is involved in creating a registry entry tied to the Control Panel\Desktop\SCRNSAVE.EXE setting, with Details indicating a .scr file. Such persistence or execution flow can be used by attackers to masquerade and load a screen saver payload. The detection relies on process image path suffix matching (rundll32.exe) and registry set telemetry that captures TargetObject and Details contents.

Reporting behind it

Related detections9 linkedT1218.011 — drag to rearrange
Malicious Zardoor Backdoor Execution via rundll32 (via process_creation)
Malicious Rundll32 Loading an Export From a User Path (via process_creation)
Renamed Regsvr32 or Rundll32 Loading a DLL With a Non-Standard Extension (via process_creation)
Malicious Rundll32 DllRegisterServer Execution From a User-Writable Path (via process_creation)
IMEEX Framework DLL Execution via Rundll32 Loading imaadp (via process_creation)
Suspicious Persistence via pcalua Launching rundll32 Control_RunDLL
Suspicious Rundll32 Executing DLL Start Export With Control Flags
Suspicious Rundll32 Execution of Timestamp-Named DLL
Suspicious Rundll32 Loading DLL from LocalAppData with Short Export (via process_creation)
Windows: Registry Set by Rundll32 for Screen Saver Execution via SCRNSAVE.EXE
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.