Windows: Detect Fodhelper.exe spawned processes indicative of UAC bypass

Flags process creation where the parent is Fodhelper.exe, a common UAC bypass execution pattern on Windows.

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windows-detect-fodhelper-exe-spawned-processes-indicative-of-uac-bypass-7f741dcf

title: "Windows: Detect Fodhelper.exe spawned processes indicative of UAC bypass"
id: 5b1cdd26-1970-4b41-83dc-a3b7282c9519
status: test
description: This rule identifies process executions where the parent image ends with \"\fodhelper.exe\". It matters because using Fodhelper.exe in this manner can be part of an attempt to bypass User Account Control and run commands with elevated privileges. Telemetry relies on Windows process creation records that include ParentImage.
references:
  - https://eqllib.readthedocs.io/en/latest/analytics/e491ce22-792f-11e9-8f5c-d46d6d62a49e.html
  - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1548.002/T1548.002.md
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_uac_bypass_fodhelper.yml
author: E.M. Anhaus (originally from Atomic Blue Detections, Tony Lambert), oscd.community, Huntrule Team
date: 2019-10-24
modified: 2021-11-27
tags:
  - attack.privilege-escalation
  - attack.t1548.002
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    ParentImage|endswith: \fodhelper.exe
  condition: selection
falsepositives:
  - Legitimate use of fodhelper.exe utility by legitimate user
level: high
license: DRL-1.1
related:
  - id: 7f741dcf-fc22-4759-87b4-9ae8376676a2
    type: derived

What it detects

This rule identifies process executions where the parent image ends with \"\fodhelper.exe\". It matters because using Fodhelper.exe in this manner can be part of an attempt to bypass User Account Control and run commands with elevated privileges. Telemetry relies on Windows process creation records that include ParentImage.

Known false positives

Legitimate use of fodhelper.exe utility by legitimate user

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.