Windows Registry IME File Value Used from Suspicious Paths

Alerts on Windows keyboard layout "Ime File" registry entries pointing to suspicious writable directory paths.

FreeUnreviewedSigmahighv1

windows-registry-ime-file-value-used-from-suspicious-paths-9d8f9bb8

title: Windows Registry IME File Value Used from Suspicious Paths
id: 0c8f0b80-da59-4a2d-8463-a240827b1274
related:
  - id: b888e3f2-224d-4435-b00b-9dd66e9ea1f1
    type: derived
  - id: 9d8f9bb8-01af-4e15-a3a2-349071530530
    type: derived
status: test
description: This rule flags registry writes or reads where the target contains both the Windows keyboard layouts key path segment and the value name "Ime File". It targets cases where the associated IME DLL path appears to reside in commonly abused writable locations such as Perflogs, public/temp directories, and user profile artifacts. Attackers may leverage IME keyboard layout loading to cause a process to load an attacker-controlled DLL after an input language change request. The detection relies on Windows registry telemetry capturing the target object path and value name.
references:
  - https://www.linkedin.com/pulse/guntior-story-advanced-bootkit-doesnt-rely-windows-disk-baranov-wue8e/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_set/registry_set_ime_suspicious_paths.yml
author: X__Junior (Nextron Systems), Huntrule Team
date: 2023-11-21
tags:
  - attack.defense-impairment
  - attack.t1685
logsource:
  product: windows
  category: registry_set
detection:
  selection_registry:
    TargetObject|contains|all:
      - \Control\Keyboard Layouts\
      - Ime File
  selection_folders_1:
    Details|contains:
      - :\Perflogs\
      - :\Users\Public\
      - :\Windows\Temp\
      - \AppData\Local\Temp\
      - \AppData\Roaming\
      - \Temporary Internet
  selection_folders_2:
    - Details|contains|all:
        - :\Users\
        - \Favorites\
    - Details|contains|all:
        - :\Users\
        - \Favourites\
    - Details|contains|all:
        - :\Users\
        - \Contacts\
  condition: selection_registry and 1 of selection_folders_*
falsepositives:
  - Unknown
level: high
license: DRL-1.1

What it detects

This rule flags registry writes or reads where the target contains both the Windows keyboard layouts key path segment and the value name "Ime File". It targets cases where the associated IME DLL path appears to reside in commonly abused writable locations such as Perflogs, public/temp directories, and user profile artifacts. Attackers may leverage IME keyboard layout loading to cause a process to load an attacker-controlled DLL after an input language change request. The detection relies on Windows registry telemetry capturing the target object path and value name.

Known false positives

Unknown

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