Potential Defense Evasion Via Right-to-Left Override — Sigma Rule

Rule metadata and linked tags

Author: Micah Babinski, @micahbabinski, Swachchhanda Shrawan Poudel (Nextron Systems), Luc Génaux. Source status: test; severity: high. Source dates: 2023-02-15 / 2026-03-20.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 7b2e055b10046f6199d2714fd1bb694826a23fd226397cee1a1095e50ee79b46

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: Potential Defense Evasion Via Right-to-Left Override
id: ad691d92-15f2-4181-9aa4-723c74f9ddc3
related:
    - id: e0552b19-5a83-4222-b141-b36184bb8d79
      type: derived
    - id: 584bca0f-3608-4402-80fd-4075ff6072e3
      type: derived
status: test
description: |
    Detects the presence of the "u202+E" character, which causes a terminal, browser, or operating system to render text in a right-to-left sequence.
    This character is used as an obfuscation and masquerading techniques by adversaries to trick users into opening malicious files.
references:
    - https://redcanary.com/blog/right-to-left-override/
    - https://www.malwarebytes.com/blog/news/2014/01/the-rtlo-method
    - https://unicode-explorer.com/c/202E
    - https://tria.ge/241015-l98snsyeje/behavioral2
    - https://unprotect.it/technique/right-to-left-override-rlo-extension-spoofing/
author: Micah Babinski, @micahbabinski, Swachchhanda Shrawan Poudel (Nextron Systems), Luc Génaux
date: 2023-02-15
modified: 2026-03-20
tags:
    - attack.stealth
    - attack.t1036.002
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains:
            - '\u202e'  # Unicode RTLO character
            - '[U+202E]'
            # Real char U+202E copied/pasted below
            - '‮'
    condition: selection
falsepositives:
    - Commandlines that contains scriptures such as arabic or hebrew might make use of this character
level: high
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_susp_right_to_left_override/info.yml

Original YAML and metadata in JSON

False positives

• Commandlines that contains scriptures such as arabic or hebrew might make use of this character

Source references

• https://redcanary.com/blog/right-to-left-override/
• https://www.malwarebytes.com/blog/news/2014/01/the-rtlo-method
• https://unicode-explorer.com/c/202E
• https://tria.ge/241015-l98snsyeje/behavioral2
• https://unprotect.it/technique/right-to-left-override-rlo-extension-spoofing/