ImageLoad via Windows Update Auto Update Client

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ImageLoad via Windows Update Auto Update Client

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Identifies abuse of the Windows Update Auto Update Client (wuauclt.exe) to load an arbitrary DLL. This behavior is used as a defense evasion technique to blend-in malicious activity with legitimate Windows software.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*
  • winlogbeat-*
  • logs-windows.*
  • endgame-*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Defense Evasion
  • Tactic: Execution
  • Data Source: Elastic Endgame
  • Data Source: Elastic Defend

Version: 108

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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process where host.os.type == "windows" and event.type == "start" and
  (process.pe.original_file_name == "wuauclt.exe" or process.name : "wuauclt.exe") and
   /* necessary windows update client args to load a dll */
   process.args : "/RunHandlerComServer" and process.args : "/UpdateDeploymentProvider" and
   /* common paths writeable by a standard user where the target DLL can be placed */
   process.args : ("C:\\Users\\*.dll", "C:\\ProgramData\\*.dll", "C:\\Windows\\Temp\\*.dll", "C:\\Windows\\Tasks\\*.dll")

Framework: MITRE ATT&CKTM