Command Line Utility Added to Accessibility Features (Windows Event Log)

id: '31349.56233'
title: Command Line Utility Added to Accessibility Features
description: 'Adversaries may establish persistence and/or elevate privileges by executing
  malicious content triggered by accessibility features. Windows contains accessibility
  features that may be launched with a key combination before a user has logged in
  (ex: when the user is on the Windows logon screen). An adversary can modify the
  way these programs are launched to get a command prompt or backdoor without logging
  in to the system. This use case detects registry modification commands or events
  adding cmd.exe or PowerShell/pwsh.exe to Accessibility Features registry keys.'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` ((TERM(EventCode=4657) OR
  "<EventID>4657<") OR (TERM(EventCode=4688) OR "<EventID>4688<" OR Type=Process))
  "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Image File Execution" "Debugger"
  ("sethc.exe" OR "utilman.exe" OR "osk.exe" OR "Magnify.exe" OR "Narrator.exe" OR
  "DisplaySwitch.exe" OR "atbroker.exe" OR "HelpPane.exe") ("cmd.exe" OR "powershell.exe"
  OR "pwsh.exe") | where (match(signature_id, "4657") and match(ObjectValueName, "(?i)Debugger")
  and match(NewValue, "(?i)(cmd|pwsh|powershell)\.exe")) or (match(signature_id, "4688")
  and match(process, "(?i)Debugger.+\x5c(cmd|pwsh|powershell)\.exe"))| table _time,
  host, user, process, parent_process_name, signature_id, ObjectValueName, NewValue
  | bin span=1s | stats values(*) as * by _time, host '
techniques:
- execution:command and scripting interpreter
- persistence:event triggered execution:accessibility features
technique_id:
- T1059
- T1546.008
data_category:
- Process command-line parameters
- Windows event logs
- Windows Registry
references:
- https://attack.mitre.org/techniques/T1546/008/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1546.008/T1546.008.md#atomic-test-1---attaches-command-prompt-as-a-debugger-to-a-list-of-target-processes
- https://www.trendmicro.com/vinfo/us/security/news/ransomware-spotlight/ransomware-spotlight-8base