ImageLoad via Windows Update Auto Update Client


ImageLoad via Windows Update Auto Update Clientedit

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:

  • winlogbeat-*
  • logs-windows.*

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



  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Defense Evasion

Version: 6

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guideedit

## Config

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.

Rule queryedit

process where event.type in ("start", "process_started") and
  ( == "wuauclt.exe" or : "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")