sigmamediumHunting

CodePage Modification Via MODE.COM To Russian Language

Detects a CodePage modification using the "mode.com" utility to Russian language. This behavior has been used by threat actors behind Dharma ransomware.

MITRE ATT&CK

T1036

defense-evasion

Detection Query

selection_img:
  - Image|endswith: \mode.com
  - OriginalFileName: MODE.COM
selection_cli:
  CommandLine|contains|all:
    - " con "
    - " cp "
    - " select="
  CommandLine|endswith:
    - =1251
    - =866
condition: all of selection_*

Author

Joseliyo Sanchez, @Joseliyo_Jstnk

Created

2024-01-17

Data Sources

windowsProcess Creation Events

Platforms

windows

References

Tags

attack.defense-evasionattack.t1036

Raw Content

title: CodePage Modification Via MODE.COM To Russian Language
id: 12fbff88-16b5-4b42-9754-cd001a789fb3
related:
    - id: d48c5ffa-3b02-4c0f-9a9e-3c275650dd0e
      type: derived
status: test
description: |
    Detects a CodePage modification using the "mode.com" utility to Russian language.
    This behavior has been used by threat actors behind Dharma ransomware.
references:
    - https://learn.microsoft.com/en-us/windows/win32/intl/code-page-identifiers
    - https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/mode
    - https://strontic.github.io/xcyclopedia/library/mode.com-59D1ED51ACB8C3D50F1306FD75F20E99.html
    - https://www.virustotal.com/gui/file/5e75ef02517afd6e8ba6462b19217dc4a5a574abb33d10eb0f2bab49d8d48c22/behavior
author: Joseliyo Sanchez, @Joseliyo_Jstnk
date: 2024-01-17
tags:
    - attack.defense-evasion
    - attack.t1036
logsource:
    category: process_creation
    product: windows
detection:
    # VT Query: behavior:"mode con cp select=1251"
    # VT Query: behavior:"mode con cp select=866"
    selection_img:
        - Image|endswith: '\mode.com'
        - OriginalFileName: 'MODE.COM'
    selection_cli:
        CommandLine|contains|all:
            - ' con '
            - ' cp '
            - ' select='
        CommandLine|endswith:
            - '=1251' # ANSI Cyrillic; Cyrillic (Windows) - Observed ITW by Dharma ransomware
            - '=866' # OEM Russian; Cyrillic (DOS) - Observed ITW by other malware
    condition: all of selection_*
falsepositives:
    - Russian speaking people changing the CodePage
level: medium