Malicious Claude Code Plugin Distributed on Cursor Marketplace

A malicious version of the Anthropic Claude Code extension was distributed on Cursor's official marketplace for roughly 11 hours, impacting approximately 5,000 developers. This high-profile supply chain attack highlights the growing security risks associated with AI tool marketplaces, where compromised plugins can expose thousands of developer environments to data theft and unauthorized access. The malicious code attempted to install persistent SSH backdoors, gather sensitive environment variables, and exfiltrate data, though implementation errors prevented successful execution on many targeted machines.