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:
- logs-endpoint.events.*
- 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
References:
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Defense Evasion
Version: 7
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 (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
-
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
-
Technique:
- Name: Signed Binary Proxy Execution
- ID: T1218
- Reference URL: https://attack.mitre.org/techniques/T1218/