UAC Bypass via DiskCleanup Scheduled Task Hijackedit

Identifies User Account Control (UAC) bypass via hijacking DiskCleanup Scheduled Task. Attackers bypass UAC to stealthily execute code with elevated permissions.

Rule type: eql

Rule indices:

  • winlogbeat-*
  • logs-endpoint.events.*
  • 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: None

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Privilege Escalation

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 == "start" and
 process.args : "/autoclean" and process.args : "/d" and
 not process.executable : ("C:\\Windows\\System32\\cleanmgr.exe",
                           "C:\\Windows\\SysWOW64\\cleanmgr.exe",
                           "C:\\Windows\\System32\\taskhostw.exe")

Framework: MITRE ATT&CKTM