huntrule

Windows Defender mpclient.dll Side-loading: MpCmdRun.exe or NisSrv.exe from Non-Default Paths

Alerts when MpCmdRun.exe or NisSrv.exe runs from non-default directories, a common indicator of possible mpclient.dll sideloading.

FreeReviewedSigma · High · v1
Product
windows
Category
process_creation
Author
Bhabesh Raj (SigmaHQ), DRL 1.1
Published
2022-08-01
Updated
2026-07-30
AnalysisDetection

ATT&CK techniques

Execution → 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 flags executions of Windows Defender binaries MpCmdRun.exe and NisSrv.exe where the process image is outside their expected default installation directories. Attackers can use DLL sideloading to load a malicious mpclient.dll in place of the legitimate dependency, enabling persistence, stealth, or privilege escalation. Telemetry required is process creation data including the full Image path for these Defender executables.

Reporting behind it

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Suspicious DLL Sideloading via ProtonVPN Executable (via image_load)
Suspicious DLL Sideloading via OneDriveStandaloneUpdater (via image_load)
Windows Defender mpclient.dll Side-loading: MpCmdRun.exe or NisSrv.exe from Non-Default Paths
Pivot detection · T1574.001 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.