Detection Against Content Copied From Browsers Executed through Run - #4261
Merged
Conversation
onurmerdogan
requested review from
P4T12ICK,
RavenTait,
ljstella,
nasbench,
patel-bhavin,
pyth0n1c,
rosplk and
tccontre
as code owners
September 7, 2026 17:41
nasbench
reviewed
Sep 7, 2026
nasbench
approved these changes
Sep 8, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Details
This detection correlates RunMRU registry modification and clipboard change from browsers. Correlation is done through the hash of the content that was copied to clipboard.
These activities combined, gives a solid base for detecting ClickFix attacks. Adversaries either asks users to manually copy or use Javascript to modify the clipboard by themselves. It first triggers the clipboard change event by the browser process. Once victim executes the copied content through Run dialog box, it triggers the modification of the RunMRU registry key.
Sysmon calculates the content hash based on UTF-16 LE encoding. Therefore RunMRU value is trimmed of its suffix and converted to UTF-16 LE, before its hash was calculated. I've also added missing Sysmon EID 24 to the repository.