Windows Proxy Execution via wuauclt.exe (UpdateDeploymentProvider/RunHandlerComServer)

Alerts when wuauclt.exe is executed with UpdateDeploymentProvider/RunHandlerComServer-related parameters indicative of proxy execution.

FreeReviewedSigma · High · v1

Product: windows
Category: process_creation
Author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), Florian Roth (Nextron Systems), Sreeman, FPT.EagleEye Team (SigmaHQ), DRL 1.1
Published: 2020-10-12
Updated: 2026-07-30

Analysis Detection

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218System Binary Proxy Execution
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags process creation where the Windows Update Client binary wuauclt.exe is launched with command-line parameters associated with UpdateDeploymentProvider and RunHandlerComServer. Attackers may abuse this legitimate Windows component to proxy or stage execution while blending in with expected update-related activity. The detection relies on Windows process creation telemetry, matching the image/OriginalFileName for wuauclt.exe and specific command-line substrings while excluding several known benign update deployment patterns.

Reporting behind it

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Windows Proxy Execution via wuauclt.exe (UpdateDeploymentProvider/RunHandlerComServer)

Pivot detection · T1218 · 9 related

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

windows-proxy-execution-via-wuauclt-exe-updatedeploymentprovider-runhandlercomse-af77cf95

title: Windows Proxy Execution via wuauclt.exe (UpdateDeploymentProvider/RunHandlerComServer)
id: 89f49e51-d3c9-45d7-84e8-72c5c4c6c3ad
related:
  - id: ba1bb0cb-73da-42de-ad3a-de10c643a5d0
    type: obsolete
  - id: d7825193-b70a-48a4-b992-8b5b3015cc11
    type: obsolete
  - id: af77cf95-c469-471c-b6a0-946c685c4798
    type: derived
status: test
description: This rule flags process creation where the Windows Update Client binary wuauclt.exe is launched with command-line parameters associated with UpdateDeploymentProvider and RunHandlerComServer. Attackers may abuse this legitimate Windows component to proxy or stage execution while blending in with expected update-related activity. The detection relies on Windows process creation telemetry, matching the image/OriginalFileName for wuauclt.exe and specific command-line substrings while excluding several known benign update deployment patterns.
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/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_wuauclt_dll_loading.yml
author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), Florian Roth (Nextron Systems), Sreeman, FPT.EagleEye Team, Huntrule 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:
    CommandLine|contains: " /UpdateDeploymentProvider UpdateDeploymentProvider.dll "
  filter_main_wuaueng:
    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
license: DRL-1.1

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