Potential Mpclient.DLL Sideloading — Sigma Rule

Rule metadata and linked tags

Author: Bhabesh Raj. Source status: test; severity: high. Source dates: 2022-08-02 / 2023-08-04.

{
  "product": "windows",
  "category": "image_load"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: acd02cec2bdd782090b3b0c37d2c5b17eafcbcb094de60790ac05ed9740aa335

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Potential Mpclient.DLL Sideloading
id: 418dc89a-9808-4b87-b1d7-e5ae0cb6effc
related:
    - id: 7002aa10-b8d4-47ae-b5ba-51ab07e228b9
      type: similar
status: test
description: Detects potential sideloading of "mpclient.dll" by Windows Defender processes ("MpCmdRun" and "NisSrv") from their non-default directory.
references:
    - https://www.sentinelone.com/blog/living-off-windows-defender-lockbit-ransomware-sideloads-cobalt-strike-through-microsoft-security-tool
author: Bhabesh Raj
date: 2022-08-02
modified: 2023-08-04
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.execution
    - attack.stealth
    - attack.t1574.001
logsource:
    product: windows
    category: image_load
detection:
    selection:
        ImageLoaded|endswith: '\mpclient.dll'
        Image|endswith:
            - '\MpCmdRun.exe'
            - '\NisSrv.exe'
    filter_main_known_locations:
        Image|startswith:
            - 'C:\Program Files (x86)\Windows Defender\'
            - 'C:\Program Files\Microsoft Security Client\'
            - 'C:\Program Files\Windows Defender\'
            - 'C:\ProgramData\Microsoft\Windows Defender\Platform\'
            - 'C:\Windows\WinSxS\'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unlikely
level: high

Original YAML and metadata in JSON

False positives

• Unlikely

Source references

• https://www.sentinelone.com/blog/living-off-windows-defender-lockbit-ransomware-sideloads-cobalt-strike-through-microsoft-security-tool