Sigma rule: Potential CVE-2026-33829 Exploitation - Windows Snipping Tool Remote File Path URI

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-caabab2e55ba, updated 2026-04-28T00:00:00.000Z.

Rule

Title
Potential CVE-2026-33829 Exploitation - Windows Snipping Tool Remote File Path URI
Status
test
Level
high
Author
Samir Bousseaden, Swachchhanda Shrawan Poudel (Nextron Systems)
Date
2026-04-28
File
rules-emerging-threats/2026/Exploits/CVE-2026-33829/proc_creation_win_exploit_cve_2026_33829.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects potential exploitation of CVE-2026-33829, a vulnerability in the Windows Snipping Tool URI handler (ms-screensketch:).
An attacker can abuse the 'filePath' parameter to supply a UNC path or HTTP URL, causing SnippingTool.exe to initiate a connection to a remote resource.
When a UNC path is used (e.g. \\attacker.com\share), this triggers an outbound NTLM authentication attempt, allowing the attacker to capture or relay the victim's Net-NTLMv2 hash.
HTTP-based paths may result in remote file loading or server-side request forgery (SSRF)-style access.
The URI can be delivered via a malicious hyperlink, phishing email, or web page.

Log source

product
windows
category
process_creation

Detection

selection:
    Image|endswith: '\SnippingTool.exe'
    CommandLine|contains:
        # '\\\\'  = literal double backslash (UNC path start); '%5C' and '%%5C' are URL-encoded variations of the same backslash character
        - 'ms-screensketch:edit?&filePath=\\\\'
        - 'ms-screensketch:edit?&filePath=%%5C'
        - 'ms-screensketch:edit?&filePath=%5C'
        - 'ms-screensketch:edit?&filePath=http'
condition: selection

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.credential-access
  • attack.t1187
  • detection.emerging-threats
  • cve.2026-33829

CVEs this rule names

MITRE ATT&CK ids this rule names

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2026/Exploits/CVE-2026-33829/proc_creation_win_exploit_cve_2026_33829.yml

Sources and licences

  • SigmaHQ

    "Potential CVE-2026-33829 Exploitation - Windows Snipping Tool Remote File Path URI" by Samir Bousseaden, Swachchhanda Shrawan Poudel (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2026/Exploits/CVE-2026-33829/proc_creation_win_exploit_cve_2026_33829.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Potential CVE-2026-33829 Exploitation - Windows Snipping Tool Remote File Path URI",
entity page, dataset version ref-caabab2e55ba, updated 2026-04-28T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/7c3a5b1d-9e2f-4a8c-b5d7-1e0f3c6a9b2d (accessed 2026-11-03).
Underlying source: SigmaHQ rule 7c3a5b1d-9e2f-4a8c-b5d7-1e0f3c6a9b2d, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.