Detection rules › Sigma

Command Executed Via Run Dialog Box - Registry

Status
test
Severity
low
Log source
category registry_set, product windows
Author
Ahmed Farouk, Nasreddine Bencherchali
Source
github.com/SigmaHQ/sigma

Detects execution of commands via the run dialog box on Windows by checking values of the "RunMRU" registry key. This technique was seen being abused by threat actors to deceive users into pasting and executing malicious commands, often disguised as CAPTCHA verification steps.

Known false positives

  • Likely

MITRE ATT&CK coverage

TacticTechniques
ExecutionNo specific technique

Telemetry coverage

Rule body

title: Command Executed Via Run Dialog Box - Registry
id: f9d091f6-f1c7-4873-a24f-050b4a02b4dd
related:
    - id: a7df0e9e-91a5-459a-a003-4cde67c2ff5d
      type: derived
status: test
description: |
    Detects execution of commands via the run dialog box on Windows by checking values of the "RunMRU" registry key.
    This technique was seen being abused by threat actors to deceive users into pasting and executing malicious commands, often disguised as CAPTCHA verification steps.
references:
    - https://www.forensafe.com/blogs/runmrukey.html
    - https://medium.com/@shaherzakaria8/downloading-trojan-lumma-infostealer-through-capatcha-1f25255a0e71
    - https://redcanary.com/blog/threat-intelligence/intelligence-insights-october-2024/
author: Ahmed Farouk, Nasreddine Bencherchali
date: 2024-11-01
tags:
    - detection.threat-hunting
    - attack.execution
logsource:
    product: windows
    category: registry_set
detection:
    selection:
        TargetObject|contains: '\Microsoft\Windows\CurrentVersion\Explorer\RunMRU'
    filter_main_mrulist:
        TargetObject|endswith: '\MRUList'
    filter_optional_ping:
        Details|contains: 'ping'
    filter_optional_generic:
        Details:
            - '%appdata%\1'
            - '%localappdata%\1'
            - '%public%\1'
            - '%temp%\1'
            - 'calc\1'
            - 'dxdiag\1'
            - 'explorer\1'
            - 'gpedit.msc\1'
            - 'mmc\1'
            - 'notepad\1'
            - 'regedit\1'
            - 'services.msc\1'
            - 'winver\1'
    condition: selection and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Likely
level: low

Stages and Predicates

Stage 0: condition

selection and not 1 of filter_main_* and not 1 of filter_optional_*

Stage 1: selection

selection:
    TargetObject|contains: '\Microsoft\Windows\CurrentVersion\Explorer\RunMRU'

Stage 2: not filter_main_mrulist

filter_main_mrulist:
    TargetObject|endswith: '\MRUList'

Stage 3: not filter_optional_*

filter_optional_ping:
    Details|contains: 'ping'
filter_optional_generic:
    Details:
        - '%appdata%\1'
        - '%localappdata%\1'
        - '%public%\1'
        - '%temp%\1'
        - 'calc\1'
        - 'dxdiag\1'
        - 'explorer\1'
        - 'gpedit.msc\1'
        - 'mmc\1'
        - 'notepad\1'
        - 'regedit\1'
        - 'services.msc\1'
        - 'winver\1'

Exclusions

The rule actively suppresses these predicates.

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
TargetObjectmatch
  • \Microsoft\Windows\CurrentVersion\Explorer\RunMRU corpus 2 (sigma 2)
field:"TargetObject" kind:match value:"\Microsoft\Windows\CurrentVersion\Explorer\RunMRU"