AI BriefingCursor removes malicious Claude Code extension version 2.1.313 after SSH backdoor attempt
·2026.10.29 21:00
Key point
The compromised extension attempted to install a persistent SSH backdoor, though the attacker's server is now offline and most backdoor steps failed due to permission errors.
Details
- Malicious version 2.1.313 of the Anthropic.claude-code extension was hosted on the Cursor VS Code marketplace for approximately 11 hours on October 29, 2026, affecting up to 4,100 users.
- The payload attempted to collect host information, add an unauthorized SSH key labeled svc-telemetry, and establish a reverse SSH tunnel to 134.209.82.225, but the attacker server has been taken offline.
- Cursor removed the package, shut down the marketplace temporarily, and confirmed no other extensions were tampered with; users are advised to check for the svc-telemetry key and run provided remediation scripts.
- The backdoor installation largely failed on standard hosts because enabling the local SSH service requires administrator privileges, which the extension lacked, though it still installed persistence mechanisms and exfiltrated host details.
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