Official Claude Code extension compromise

A trojanized Claude Code extension, versions 2.1.312 and 2.1.313, was served on the Cursor Marketplace for roughly eleven hours on one day, according to Cursor. Phorion's analysis shows a prepended loader that plants an SSH key, opens a reverse tunnel, adds persistence and beacons host details. Cursor says errors in the code would make the SSH step fail outside unusual privilege cases, and the attacker server has been taken down. The npm and OpenVSX packages were reportedly unaffected. Teams should check installed extension versions and remove the persistence files.