System Language Discovery via Reg.Exe

Detects the usage of Reg.Exe to query system language settings. Attackers may discover the system language to determine the geographic location of victims, customize payloads for specific regions, or avoid targeting certain locales to evade detection.

title: System Language Discovery via Reg.Exe
id: c43a5405-e8e1-4221-9ac9-dbe3fa14e886
status: experimental
description: |
    Detects the usage of Reg.Exe to query system language settings.
    Attackers may discover the system language to determine the geographic location of victims, customize payloads for specific regions,
    or avoid targeting certain locales to evade detection.
references:
    - https://scythe.io/threat-thursday/threatthursday-darkside-ransomware
author: Marco Pedrinazzi (@pedrinazziM) (InTheCyber)
date: 2026-01-09
tags:
    - attack.discovery
    - attack.t1614.001
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\reg.exe'
        - OriginalFileName: 'reg.exe'
    selection_cli:
        CommandLine|contains|all:
            - 'query'
            - 'Control\Nls\Language'
    condition: all of selection_*
falsepositives:
    - Unknown
level: medium
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_reg_system_language_discovery/info.yml
simulation:
    - type: atomic-red-team
      name: Discover System Language by Registry Query
      technique: T1614.001
      atomic_guid: 631d4cf1-42c9-4209-8fe9-6bd4de9421be

• T1614.001System Language Discovery

• https://scythe.io/threat-thursday/threatthursday-darkside-ransomware↗