Windows Process Creation: AtBroker.exe Launching Assistive Technology Apps

Alerts on Windows process starts of AtBroker.exe with "start" that don’t match known built-in accessibility parameters.

FreeReviewedSigma · Medium · v2

Product: windows
Category: process_creation
Author: Mateusz Wydra, oscd.community (SigmaHQ), DRL 1.1
Published: 2020-10-12
Updated: 2026-07-31

ATT&CK techniques

Defense Evasion

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
- T1218System Binary Proxy Execution
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies execution of AtBroker.exe with a command line containing the substring "start" while excluding known built-in assistive technology feature arguments. Attackers may leverage this workflow to launch accessibility-related components in a less common manner, blending into legitimate user activity. It relies on Windows process creation telemetry, specifically the executable path/name, original file name, and command-line contents.

Reporting behind it

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Windows Process Creation: AtBroker.exe Launching Assistive Technology Apps

Pivot detection · T1218 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

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

windows-execution-of-assistive-technology-app-via-atbroker-exe-non-built-in-f24bcaea

title: "Windows Process Creation: AtBroker.exe Launching Assistive Technology Apps"
id: 4b59431c-045a-48a8-863f-03372f70da10
status: test
description: This rule identifies execution of AtBroker.exe with a command line containing the substring "start" while excluding known built-in assistive technology feature arguments. Attackers may leverage this workflow to launch accessibility-related components in a less common manner, blending into legitimate user activity. It relies on Windows process creation telemetry, specifically the executable path/name, original file name, and command-line contents.
references:
  - http://www.hexacorn.com/blog/2016/07/22/beyond-good-ol-run-key-part-42/
  - https://lolbas-project.github.io/lolbas/Binaries/Atbroker/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/process_creation/proc_creation_win_atbroker_uncommon_ats_execution.yml
author: Mateusz Wydra, oscd.community, Huntrule Team
date: 2020-10-12
modified: 2024-03-06
tags:
  - attack.stealth
  - attack.t1218
logsource:
  category: process_creation
  product: windows
detection:
  selection_img:
    - Image|endswith: \AtBroker.exe
    - OriginalFileName: AtBroker.exe
  selection_cli:
    CommandLine|contains: start
  filter_main_builtin:
    CommandLine|contains:
      - animations
      - audiodescription
      - caretbrowsing
      - caretwidth
      - colorfiltering
      - cursorindicator
      - cursorscheme
      - filterkeys
      - focusborderheight
      - focusborderwidth
      - highcontrast
      - keyboardcues
      - keyboardpref
      - livecaptions
      - magnifierpane
      - messageduration
      - minimumhitradius
      - mousekeys
      - Narrator
      - osk
      - overlappedcontent
      - showsounds
      - soundsentry
      - speechreco
      - stickykeys
      - togglekeys
      - voiceaccess
      - windowarranging
      - windowtracking
      - windowtrackingtimeout
      - windowtrackingzorder
  filter_optional_java:
    CommandLine|contains: Oracle_JavaAccessBridge
  condition: all of selection_* and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
  - Legitimate, non-default assistive technology applications execution
level: medium
license: DRL-1.1
related:
  - id: f24bcaea-0cd1-11eb-adc1-0242ac120002
    type: derived

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