Uncommon Extension In Keyboard Layout IME File Registry Value — Sigma Rule

Rule metadata and linked tags

Author: X__Junior (Nextron Systems). Source status: test; severity: high. Source dates: 2023-11-21 / not supplied.

{
  "product": "windows",
  "category": "registry_set"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 7c84c4a2029db3ff0ef781e05ecd27fdd0ff772bbd5cfc0db0e349feb7a80aa1

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Uncommon Extension In Keyboard Layout IME File Registry Value
id: b888e3f2-224d-4435-b00b-9dd66e9ea1f1
related:
    - id: 9d8f9bb8-01af-4e15-a3a2-349071530530
      type: derived
status: test
description: |
    Detects usage of Windows Input Method Editor (IME) keyboard layout feature, which allows an attacker to load a DLL into the process after sending the WM_INPUTLANGCHANGEREQUEST message.
    Before doing this, the client needs to register the DLL in a special registry key that is assumed to implement this keyboard layout. This registry key should store a value named "Ime File" with a DLL path.
    IMEs are essential for languages that have more characters than can be represented on a standard keyboard, such as Chinese, Japanese, and Korean.
references:
    - https://www.linkedin.com/pulse/guntior-story-advanced-bootkit-doesnt-rely-windows-disk-baranov-wue8e/
author: X__Junior (Nextron Systems)
date: 2023-11-21
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    product: windows
    category: registry_set
detection:
    selection:
        TargetObject|contains|all:
            - '\Control\Keyboard Layouts\'
            - 'Ime File'
    filter_main_known_extension:
        Details|endswith: '.ime'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - IMEs are essential for languages that have more characters than can be represented on a standard keyboard, such as Chinese, Japanese, and Korean.
level: high

Original YAML and metadata in JSON

False positives

• IMEs are essential for languages that have more characters than can be represented on a standard keyboard, such as Chinese, Japanese, and Korean.

Source references

• https://www.linkedin.com/pulse/guntior-story-advanced-bootkit-doesnt-rely-windows-disk-baranov-wue8e/