Windows Registry RunMRU Tampering with HTTP/HTTPS and Script Execution Indicators

Alerts on Windows RunMRU registry changes containing HTTP/HTTPS URLs plus captcha/automation or command execution indicators.

FreeReviewedSigma · High · v1

Product: windows
Category: registry_set
Author: Swachchhanda Shrawan Poudel (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2025-03-25
Updated: 2026-07-30

Analysis Detection

ATT&CK techniques

Execution

Recon
Resource Dev
Initial Access
Execution
- T1204.001Malicious Link
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule flags Windows registry Set operations targeting Explorer RunMRU entries where the stored Details contain HTTP or HTTPS URLs. It further narrows matches to entries that include common fake-interaction and automation-bypass terms (for example, captcha/challenge/verification) and/or strings associated with command or scripting execution tools (such as PowerShell, cmd, mshta, certutil, curl, wget, and mshta). This combination matters because it can reflect user-driven phishing lure workflows that lead to pasting and executing attacker-controlled content via the Run dialog. The detection relies on registry_set telemetry for RunMRU TargetObject and the presence of specific URL and keyword patterns in the Details field.

Reporting behind it

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Windows Registry RunMRU Tampering with HTTP/HTTPS and Script Execution Indicators

Pivot detection · T1204.001 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-registry-runmru-tampering-with-http-https-and-script-execution-indicator-f5fe36cf

title: Windows Registry RunMRU Tampering with HTTP/HTTPS and Script Execution Indicators
id: a1e0babf-471a-429a-a736-4c88fd180529
related:
  - id: d487ed4a-fd24-436d-a0b2-f4e95f7b2635
    type: similar
  - id: f5fe36cf-f1ec-4c23-903d-09a3110f6bbb
    type: derived
status: experimental
description: This rule flags Windows registry Set operations targeting Explorer RunMRU entries where the stored Details contain HTTP or HTTPS URLs. It further narrows matches to entries that include common fake-interaction and automation-bypass terms (for example, captcha/challenge/verification) and/or strings associated with command or scripting execution tools (such as PowerShell, cmd, mshta, certutil, curl, wget, and mshta). This combination matters because it can reflect user-driven phishing lure workflows that lead to pasting and executing attacker-controlled content via the Run dialog. The detection relies on registry_set telemetry for RunMRU TargetObject and the presence of specific URL and keyword patterns in the Details field.
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/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_set/registry_set_potential_clickfix_execution.yml
author: Swachchhanda Shrawan Poudel (Nextron Systems), Huntrule Team
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:
        - 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
license: DRL-1.1

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