T1036.002_right-to-left-override

DevOps & Security

Adversaries may abuse the right-to-left override (RTLO or RLO) character (U+202E) to disguise a string and/or file name to make it appear benign.

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/mitre_attack/TA0005_defense-evasion/T1036.002_right-to-left-override/SKILL.md

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T1036.002 Right-to-Left Override

Sub-technique of: T1036

High-Level Description

Adversaries may abuse the right-to-left override (RTLO or RLO) character (U+202E) to disguise a string and/or file name to make it appear benign. RTLO is a non-printing Unicode character that causes the text that follows it to be displayed in reverse. For example, a Windows screensaver executable named March 25 \u202Excod.scr will display as March 25 rcs.docx. A JavaScript file named photo_high_re\u202Egnp.js will be displayed as photo_high_resj.png.

Adversaries may abuse the RTLO character as a means of tricking a user into executing what they think is a benign file type. A common use of this technique is with Spearphishing Attachment/Malicious File since it can trick both end users and defenders if they are not aware of how their tools display and render the RTLO character. Use of the RTLO character has been seen in many targeted intrusion attempts and criminal activity. RTLO can be used in the Windows Registry as well, where regedit.exe displays the reversed characters but the command line tool reg.exe does not by default.

Kill Chain Phase

Defense Evasion (TA0005)

Platforms: Linux, macOS, Windows

What to Check

Identify if Right-to-Left Override technique is applicable to target environment
Check Linux systems for indicators of Right-to-Left Override
Check macOS systems for indicators of Right-to-Left Override
Check Windows systems for indicators of Right-to-Left Override
Assess detection coverage (1 detection strategies)

How to Test

Manual Testing

Identify Attack Surface: Determine if the target environment is susceptible to Right-to-Left Override by examining the target platforms (Linux, macOS, Windows).
Assess Existing Defenses: Review whether mitigations for T1036.002 are in place. If defenses are absent or misconfigured, this technique may be exploitable.
Execute Test: Use tools and methods described in the MITRE ATT&CK page and external references below.

Note: No Atomic Red Team tests available for this technique. See Atomic Red Team GitHub for updates.

Remediation Guide

No specific mitigations documented for this technique.

Detection

Right-to-Left Override Masquerading Detection via Filename and Execution Context

Risk Assessment

Finding	Severity	Impact
Right-to-Left Override technique applicable	High	Defense Evasion

CWE Categories

CWE ID	Title
CWE-693	Protection Mechanism Failure