Anthropic Claude VS Code extension on Cursor backdoored (v2.1.313)
A malicious version (2.1.313) of Anthropic’s official Claude VS Code extension was published via Anthropic’s account on the Cursor marketplace and was available for nearly 12 hours, potentially affecting up to 5,000 users. The backdoored build attempted host reconnaissance (collecting hostname, user, OS, env variables), to install a persistent SSH backdoor and open a reverse SSH tunnel; Cursor removed the package, blocked distribution, rotated keys and reopened the marketplace, while Anthropic has not publicly notified customers.