Compromised Claude Code extension planted SSH access through Cursor marketplace

A malicious version of the Claude Code extension distributed through Cursor's extension marketplace added an attacker's SSH key and installed persistence on users' computers, The Hacker News reported. Cursor said at most 5,000 users installed the altered version on October 29 and briefly took down its marketplace to remove the malware. The package identified itself as version 2.1.313 and attempted to enable SSH access through a reverse tunnel while sending host details to the attacker. On most Windows and macOS hosts, enabling SSH failed because the extension lacked administrator rights, but the key, persistence and reconnaissance steps still ran. The malicious version has been removed, and Anthropic published version 2.1.314 to Open VSX and Microsoft's marketplace.