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Claude Desktop quietly installs browser access files without user consent, researcher finds
Claude Desktop installs browser manifest files that grant three Chrome extensions automatic access to the app without user permission. Anthropic has not responded, and deleting the files manually won't stick-the app recreates them on relaunch.
Claude Desktop's Hidden Browser Access Raises Privacy Questions
A security researcher has discovered that Claude Desktop automatically installs files that give browser extensions access to the desktop app without explicit user consent. The finding has sparked concerns about how much system access the application actually has.
The issue centers on Native Messaging, an API that allows browsers and desktop applications to communicate with each other. Security researcher Alexander Hanff found that installing Claude Desktop adds a manifest file to several Chromium-based browsers-including browsers not yet installed on the machine. The file pre-approves three Chrome extension IDs for automatic access, bypassing the normal permission prompt users typically see.
What was discovered
Hanff discovered the behavior on his Mac during a debug session. He had never installed any Claude extensions, yet the manifest files were present across multiple Chromium browsers on his system.
The manifest file registers Claude Desktop as a Native Messaging host. Once registered, any of the three whitelisted extensions can connect to Claude Desktop immediately upon installation, without asking the user for permission.
Hanff characterized the approach as "a dark pattern" and said it violates European Union computer access and misuse laws. His findings have been validated by other security researchers and reported independently across Mastodon, Reddit, and LinkedIn.
The behavior has been confirmed on macOS. The status on Windows and Linux remains unverified, according to security firm Malwarebytes.
Anthropic hasn't responded
The company has made no public statement about the discovery. Claude Desktop's official documentation contains no mention of this behavior.
For AI for Writers who use Claude Desktop for content creation, the lack of clarity is problematic. Users deserve to know what system-level access applications request.
Removing the files is difficult but possible
Users can delete the manifest files manually. Run this command in Terminal to locate them:
$ find ~/Library/Application\ Support -name "com.anthropic.claude_browser_extension*"
However, deleting the files will not prevent Claude Desktop from recreating them the next time the app runs. The only way to stop the behavior entirely is to uninstall Claude Desktop-at least until Anthropic addresses the issue.
Since Claude Desktop is essentially a web wrapper, users can access most features through the web interface instead.