Windows Process Creation: Empire PowerShell UAC Bypass CommandLine Pattern

Flags Windows process creation events running Empire-style PowerShell UAC bypass command fragments.

FreeReviewedSigma · Critical · v2
Product
windows
Category
process_creation
Author
Ecco (SigmaHQ), DRL 1.1
Published
2019-08-30
Updated
2026-07-31
title: "Windows Process Creation: Empire PowerShell UAC Bypass CommandLine Pattern"
id: ebc985ea-267a-4a32-b1c8-e8ae2d98f837
status: stable
description: This rule matches PowerShell command lines that include a specific pattern used to set a variable from the HKCU\Software\Microsoft\Windows Update\Update registry value, consistent with some Empire PowerShell UAC bypass methods. Attackers use UAC bypass techniques to elevate privileges and execute subsequent actions with higher integrity. The detection relies on process creation telemetry and command-line contents containing the exact substrings defined in the rule.
references:
  - https://github.com/EmpireProject/Empire/blob/e37fb2eef8ff8f5a0a689f1589f424906fe13055/data/module_source/privesc/Invoke-EventVwrBypass.ps1#L64
  - https://github.com/EmpireProject/Empire/blob/e37fb2eef8ff8f5a0a689f1589f424906fe13055/data/module_source/privesc/Invoke-FodHelperBypass.ps1#L64
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_hktl_empire_powershell_uac_bypass.yml
author: Ecco, Huntrule Team
date: 2019-08-30
modified: 2023-02-21
tags:
  - attack.privilege-escalation
  - attack.t1548.002
  - car.2019-04-001
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    CommandLine|contains:
      - " -NoP -NonI -w Hidden -c $x=$((gp HKCU:Software\\Microsoft\\Windows Update).Update)"
      - " -NoP -NonI -c $x=$((gp HKCU:Software\\Microsoft\\Windows Update).Update);"
  condition: selection
falsepositives:
  - Unknown
level: critical
license: DRL-1.1
related:
  - id: 3268b746-88d8-4cd3-bffc-30077d02c787
    type: derived