Detection rules › Sigma

Uncommon Extension In Keyboard Layout IME File Registry Value

Severity
high
Author
X__Junior (Nextron Systems)
Source
upstream

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.

MITRE ATT&CK coverage

TacticTechniques
Defense EvasionT1562.001 Impair Defenses: Disable or Modify Tools

Event coverage

ProviderEvent IDTitle
Sysmon13RegistryEvent (Value Set)

Stages and Predicates

Stage 1: selection

TargetObject|contains: 'Ime File'
TargetObject|contains: '\Control\Keyboard Layouts\'

Stage 2: not 1 of filter_main_known_extension

Details|endswith: .ime

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Detailsends_with
  • .ime
TargetObjectmatch
  • Ime File corpus 2 (sigma 2)
  • \Control\Keyboard Layouts\ corpus 2 (sigma 2)