Official Claude Code VS Code Extension Compromised to Install Persistent SSH Backdoor

The official Anthropic Claude Code extension on the Open VSX registry was compromised to deliver a persistent SSH backdoor on infected systems. The attack was traced back to a compromise of the Cursor Marketplace, an AI coding platform, which temporarily took down its service to remove the malware. The backdoor was designed to maintain persistent access to victim machines via SSH. This represents a significant supply chain attack targeting developer tools and AI coding assistants. The incident highlights risks associated with third-party extension marketplaces used by developers. Cursor took immediate remediation steps upon discovery of the malicious code.