RunMRU Registry Key Deletion — Sigma Rule

Rule metadata and linked tags

Author: Swachchhanda Shrawan Poudel (Nextron Systems). Source status: experimental; severity: high. Source dates: 2025-09-25 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 47eff2586d7a86a277c2b144639cf9b3d2dee4d37ddf76f5857dae29c62bf496

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: RunMRU Registry Key Deletion
id: c11aecef-9c37-45a6-9c07-bc0782f963fd
related:
    - id: 3a9b8c1e-5b2e-4f7a-9d1c-2a7f3b6e1c55
      type: similar
status: experimental
description: |
    Detects deletion of the RunMRU registry key, which stores the history of commands executed via the Run dialog.
    In the clickfix techniques, the phishing lures instruct users to open a run dialog through (Win + R) and execute malicious commands.
    Adversaries may delete this key to cover their tracks after executing commands.
references:
    - https://www.zscaler.com/blogs/security-research/coldriver-updates-arsenal-baitswitch-and-simplefix
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-09-25
tags:
    - attack.stealth
    - attack.t1070.003
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\reg.exe'
        - OriginalFileName: 'reg.exe'
    selection_cli:
        CommandLine|contains|all:
            - ' del'
            - '\Software\Microsoft\Windows\CurrentVersion\Explorer\RunMRU'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.zscaler.com/blogs/security-research/coldriver-updates-arsenal-baitswitch-and-simplefix