Suspicious wuauclt.exe Process Creation on Windows with Empty Command-Line Flags

Alert on Windows Update Agent wuauclt.exe launches that have command lines ending with no flags/arguments.

FreeReviewedSigma · High · v1

Product: windows
Category: process_creation
Author: Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2022-02-26
Updated: 2026-07-30

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1036Masquerading
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags Windows process creation events where wuauclt.exe starts without any command-line flags, as indicated by a command line that ends with Wuauclt or Wuauclt.exe. Attackers may misuse Windows Update-related executables to blend in with normal system activity while performing malicious actions. The detection relies on process creation telemetry, matching the executable image/filename and the pattern of the command line ending without arguments.

Reporting behind it

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Suspicious wuauclt.exe Process Creation on Windows with Empty Command-Line Flags

Pivot detection · T1036 · 9 related

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

suspicious-wuauclt-exe-process-creation-on-windows-with-empty-command-line-flags-52d097e2

title: Suspicious wuauclt.exe Process Creation on Windows with Empty Command-Line Flags
id: c1933932-a874-49dd-bba6-04f33748bd83
status: test
description: This rule flags Windows process creation events where wuauclt.exe starts without any command-line flags, as indicated by a command line that ends with Wuauclt or Wuauclt.exe. Attackers may misuse Windows Update-related executables to blend in with normal system activity while performing malicious actions. The detection relies on process creation telemetry, matching the executable image/filename and the pattern of the command line ending without arguments.
references:
  - https://redcanary.com/blog/blackbyte-ransomware/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_wuauclt_no_cli_flags_execution.yml
author: Florian Roth (Nextron Systems), Huntrule Team
date: 2022-02-26
modified: 2023-11-11
tags:
  - attack.stealth
  - attack.t1036
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    - Image|endswith: \Wuauclt.exe
    - OriginalFileName: Wuauclt.exe
  selection_cli:
    CommandLine|endswith:
      - Wuauclt
      - Wuauclt.exe
  condition: all of selection*
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: 52d097e2-063e-4c9c-8fbb-855c8948d135
    type: derived

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