FWIW the compromised version, 2.1.313, was removed from OpenVSX. 2.1.314 is the ‘fixed’ version.
Post by Kevin Beaumont
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Anthropic's Claude Code Cursor extension was also compromised, same remote access backdoor https://cursor.com/blog/claude-code-extension-security-notice
Anthropic still haven't admitted what has happened.
Cursor
Security notice — malicious version of Anthropic.claude-code (2.1.313) identified in the Cursor Extension Marketplace · Cursor
Today we identified a security incident involving a specific extension package in the Cursor VS Code extension Marketplace: Anthropic.claude-code version 2.1.313.
I've written a blog - Anthropic have been hacked to deliver remote access malware to millions of endpoints where developers use Claude Code.
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Threat actor's C2 server is now offline.
C2 server collected for each victim endpoint:
- hostname
- username
- OS
- architecture
- home directory path
- environment variable names
- working directories
- configured Git email
It then ran a reverse SSH connection allowing the threat actor to pick and chose which victims to have hands on keyboard access to.
I'm confirmed the new, replacement versions Anthropic published overnight (which auto update) do *not* remove the prior backdoors and recon activity. So SSH still reverse calls out etc, you need to manually remediate every impacted VSCode and Cursor system.
Anthropic *must* tell customers what happened in a completely transparent way.