Sigma Rule Library

Potentially Suspicious Command Executed Via Run Dialog Box - Registry

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.

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Detection logic

selection_key

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

selection_powershell_command

Details|contains:
  - powershell
  - pwsh

selection_powershell_susp_keywords

Details|contains:
  - " -e "
  - " -ec "
  - " -en "
  - " -enc "
  - " -enco"
  - ftp
  - Hidden
  - http
  - iex
  - Invoke-

selection_wmic_command

Details|contains: wmic

selection_wmic_susp_keywords

Details|contains:
  - shadowcopy
  - process call create

Condition

selection_key and (all of selection_powershell_* or all of selection_wmic_*)

Raw YAML

title: Potentially Suspicious Command Executed Via Run Dialog Box - Registry
id: a7df0e9e-91a5-459a-a003-4cde67c2ff5d
related:
    - id: f9d091f6-f1c7-4873-a24f-050b4a02b4dd
      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://medium.com/@ahmed.moh.farou2/fake-captcha-campaign-on-arabic-pirated-movie-sites-delivers-lumma-stealer-4f203f7adabf
    - https://medium.com/@shaherzakaria8/downloading-trojan-lumma-infostealer-through-capatcha-1f25255a0e71
    - https://www.forensafe.com/blogs/runmrukey.html
    - https://redcanary.com/blog/threat-intelligence/intelligence-insights-october-2024/
author: Ahmed Farouk, Nasreddine Bencherchali
date: 2024-11-01
tags:
    - attack.execution
    - attack.t1059.001
logsource:
    product: windows
    category: registry_set
detection:
    selection_key:
        TargetObject|contains: '\Microsoft\Windows\CurrentVersion\Explorer\RunMRU'
    selection_powershell_command:
        Details|contains:
            - 'powershell'
            - 'pwsh'
    selection_powershell_susp_keywords:
        Details|contains:
            - ' -e '
            - ' -ec '
            - ' -en '
            - ' -enc '
            - ' -enco'
            - 'ftp'
            - 'Hidden'
            - 'http'
            - 'iex'
            - 'Invoke-'
    selection_wmic_command:
        Details|contains: 'wmic'
    selection_wmic_susp_keywords:
        Details|contains:
            - 'shadowcopy'
            - 'process call create'
    condition: selection_key and (all of selection_powershell_* or all of selection_wmic_*)
falsepositives:
    - Unknown
level: high

False positives

  • Unknown

References

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