Cursor Says Its Marketplace Was Source of Backdoored Claude Code Build

Cursor identified its marketplace as the source of a backdoored Claude Code extension, whose code was designed to give attackers persistent remote access to developer machines. The analyzed package was version 2.1.313 for macOS on Apple Silicon. A 66-line loader placed before the extension’s normal code could run when the extension loaded, even if a user had not started a Claude conversation. The loader was designed to add an attacker-controlled SSH key labeled svc-telemetry, create startup persistence and open a reverse tunnel to 134.209.82.225. It also sent host information to that server on port 8099. The distribution path is disputed.

Source: TokenPost