Sigma Rule Library

Potential ClickFix Execution Pattern - Registry

Detects potential ClickFix malware execution patterns by monitoring registry modifications in RunMRU keys containing HTTP/HTTPS links. ClickFix is known to be distributed through phishing campaigns and uses techniques like clipboard hijacking and fake CAPTCHA pages. Through the fakecaptcha pages, the adversary tricks users into opening the Run dialog box and pasting clipboard-hijacked content, such as one-liners that execute remotely hosted malicious files or scripts.

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Detection logic

selection_registry

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

selection_details

Details|contains:
  - http://
  - https://

selection_susp_pattern

- Details|contains:
    - account
    - anti-bot
    - botcheck
    - captcha
    - challenge
    - confirmation
    - fraud
    - human
    - identification
    - identificator
    - identity
    - robot
    - validation
    - verification
    - verify
- Details|contains:
    - "%comspec%"
    - bitsadmin
    - certutil
    - cmd
    - cscript
    - curl
    - finger
    - mshta
    - powershell
    - pwsh
    - regsvr32
    - rundll32
    - schtasks
    - wget
    - wscript

Condition

all of selection_*

Raw YAML

title: Potential ClickFix Execution Pattern - Registry
id: f5fe36cf-f1ec-4c23-903d-09a3110f6bbb
related:
    - id: d487ed4a-fd24-436d-a0b2-f4e95f7b2635
      type: similar
status: experimental
description: |
    Detects potential ClickFix malware execution patterns by monitoring registry modifications in RunMRU keys containing HTTP/HTTPS links.
    ClickFix is known to be distributed through phishing campaigns and uses techniques like clipboard hijacking and fake CAPTCHA pages.
    Through the fakecaptcha pages, the adversary tricks users into opening the Run dialog box and pasting clipboard-hijacked content,
    such as one-liners that execute remotely hosted malicious files or scripts.
references:
    - https://github.com/JohnHammond/recaptcha-phish
    - https://www.zscaler.com/blogs/security-research/deepseek-lure-using-captchas-spread-malware
    - https://www.threatdown.com/blog/clipboard-hijacker-tries-to-install-a-trojan/
    - https://app.any.run/tasks/5c16b4db-4b36-4039-a0ed-9b09abff8be2
    - https://www.esentire.com/security-advisories/netsupport-rat-clickfix-distribution
    - https://medium.com/@boutnaru/the-windows-foreniscs-journey-run-mru-run-dialog-box-most-recently-used-57375a02d724
    - https://unit42.paloaltonetworks.com/preventing-clickfix-attack-vector/
    - https://medium.com/@poudelswachchhanda123/preventing-lnk-and-fakecaptcha-threats-a-system-hardening-approach-2f7b7ed2e493
    - https://www.scpx.com.au/2025/11/16/decades-old-finger-protocol-abused-in-clickfix-malware-attacks/
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-03-25
modified: 2025-11-19
tags:
    - attack.execution
    - attack.t1204.001
logsource:
    category: registry_set
    product: windows
detection:
    selection_registry:
        TargetObject|contains: '\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\RunMRU\'
    selection_details:
        Details|contains:
            - 'http://'
            - 'https://'
    selection_susp_pattern:
        - Details|contains:
              # Add more suspicious keywords
              - 'account'
              - 'anti-bot'
              - 'botcheck'
              - 'captcha'
              - 'challenge'
              - 'confirmation'
              - 'fraud'
              - 'human'
              - 'identification'
              - 'identificator'
              - 'identity'
              - 'robot'
              - 'validation'
              - 'verification'
              - 'verify'
        - Details|contains:
              - '%comspec%'
              - 'bitsadmin'
              - 'certutil'
              - 'cmd'
              - 'cscript'
              - 'curl'
              - 'finger'
              - 'mshta'
              - 'powershell'
              - 'pwsh'
              - 'regsvr32'
              - 'rundll32'
              - 'schtasks'
              - 'wget'
              - 'wscript'
    condition: all of selection_*
falsepositives:
    - Legitimate applications using RunMRU with HTTP links
level: high

False positives

  • Legitimate applications using RunMRU with HTTP links

References

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