Proxy Execution Via Wuauclt.EXE — Sigma Rule

Rule metadata and linked tags

Author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), Florian Roth (Nextron Systems), Sreeman, FPT.EagleEye Team. Source status: test; severity: high. Source dates: 2020-10-12 / 2023-11-11.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: d50f5048c54d3b1aa040a89233e6adb6c6a7ca849850ea6564329f1ce1eec1c8

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: Proxy Execution Via Wuauclt.EXE
id: af77cf95-c469-471c-b6a0-946c685c4798
related:
    - id: ba1bb0cb-73da-42de-ad3a-de10c643a5d0
      type: obsolete
    - id: d7825193-b70a-48a4-b992-8b5b3015cc11
      type: obsolete
status: test
description: Detects the use of the Windows Update Client binary (wuauclt.exe) for proxy execution.
references:
    - https://dtm.uk/wuauclt/
    - https://blog.malwarebytes.com/threat-intelligence/2022/01/north-koreas-lazarus-apt-leverages-windows-update-client-github-in-latest-campaign/
author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), Florian Roth (Nextron Systems), Sreeman, FPT.EagleEye Team
date: 2020-10-12
modified: 2023-11-11
tags:
    - attack.stealth
    - attack.t1218
    - attack.execution
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\wuauclt.exe'
        - OriginalFileName: 'wuauclt.exe'
    selection_cli:
        CommandLine|contains|all:
            - 'UpdateDeploymentProvider'
            - 'RunHandlerComServer'
    filter_main_generic:
        # Note: Please enhance this if you find the full path
        CommandLine|contains: ' /UpdateDeploymentProvider UpdateDeploymentProvider.dll '
    filter_main_wuaueng:
        # Note: Please enhance this if you find the full path
        CommandLine|contains: ' wuaueng.dll '
    filter_main_uus:
        CommandLine|contains:
            - ':\Windows\UUS\Packages\Preview\amd64\updatedeploy.dll /ClassId'
            - ':\Windows\UUS\amd64\UpdateDeploy.dll /ClassId'
    filter_main_winsxs:
        CommandLine|contains|all:
            - ':\Windows\WinSxS\'
            - '\UpdateDeploy.dll /ClassId '
    condition: all of selection_* and not 1 of filter_main_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://dtm.uk/wuauclt/
• https://blog.malwarebytes.com/threat-intelligence/2022/01/north-koreas-lazarus-apt-leverages-windows-update-client-github-in-latest-campaign/