Check your machine for the backdoored Claude Code editor extension and clean up properly

What you end up with

Uninstalling the extension does not remove what it added, so check the SSH keys and startup entries by hand and rotate credentials from a different, clean machine.

What you get

• A plain-language summary of the workflow
• A fill-in prompt template
• What to watch out for
• A link to the original source

Who it is for

Builders who already use AI agents and want a proven workflow they can copy into their own project.

Works with

Solid chips: the agent is named in this listing's own tools list. Dashed chip: Plain Markdown, so it also pastes into other agents such as Grok Bot, Hermes, OpenClaw or Muse. We list those as compatible by format only, not as tested.

Tools needed

Cost to run: Free with the agent plan you already use.
Time to result: One working session

How it works

1. Check which Claude Code extension version each editor installed and wh

   Check which Claude Code extension version each editor installed and when (the extensions folder and the editor's extension log).

   Expected: Done before you move to the next step.

2. If 2.1.313 was ever installed, list ~/.ssh/authorized_keys and remove

   If 2.1.313 was ever installed, list ~/.ssh/authorized_keys and remove any key you do not recognise, starting with one labelled svc-telemetry.

   Expected: Done before you move to the next step.

3. Look for the startup entries named in the vendor notice for your platf

   Look for the startup entries named in the vendor notice for your platform and remove them.

   Expected: Done before you move to the next step.

4. Update to 2.1.314 or later, then rotate SSH keys, API tokens and cloud

   Update to 2.1.314 or later, then rotate SSH keys, API tokens and cloud credentials from a clean machine.

   Expected: Done before you move to the next step.

5. Turn off extension auto-update until you have an allow-list and a wait

   Turn off extension auto-update until you have an allow-list and a waiting period for new versions.

   Expected: Done before you move to the next step.

Sample prompt from the pack

Apply this workflow to [your project]:
1. Check which Claude Code extension version each editor installed and when (the extensions folder and the editor's extension log).
2. If 2.1.313 was ever installed, list ~/.ssh/authorized_keys and remove any key you do not recognise, starting with one labelled svc-telemetry.
3. Look for the startup entries named in the vendor notice for your platform and remove them.
4. Update to 2.1.314 or later, then rotate SSH keys, API tokens and cloud credentials from a clean machine.
5. Turn off extension auto-update until you have an allow-list and a waiting period for new versions.
Stop and ask me before anything irreversible: deploys, payments, sends or deletes.

Free preview of the file

# Check your machine for the backdoored Claude Code editor extension and clean up properly

PaperChase agent use case (free feed entry), version 1.0. Source: [Cursor (security notice); analysis by Phorion](https://cursor.com/blog/claude-code-extension-security-notice), 2026-10-29.

## What they did

Cursor published a notice that a malicious version of the Anthropic Claude Code extension was available from its marketplace from roughly 2:27am to 1:35pm PT on Oct 29, 2026, and pushed a clean 2.1.314. Phorion's write-up describes what the bad build did: it wrote a new key into ~/.ssh/authorized_keys, tried to open a reverse tunnel to an outside server, beaconed out, and added startup entries (a LaunchAgent on macOS, an @reboot crontab line on Linux, hidden files under ~/.config, a scheduled task or Startup script on Windows). Users on r/ClaudeAI and r/ClaudeCode compared notes and a read-only check script was published on GitHub.

## Worth knowing

Uninstalling the extension does not remove what it added, so check the SSH keys and startup entries by hand and rotate credentials from a different, clean machine. Only machines that installed or auto-updated to 2.1.313 in that window are affected; confirm the version history before you panic. Read the vendor notice yourself rather than trusting a summary, including this one.

Worth knowing

• Uninstalling the extension does not remove what it added, so check the SSH keys and startup entries by hand and rotate credentials from a different, clean machine. Only machines that installed or auto-updated to 2.1.313 in that window are affected; confirm the version history before you panic. Read the vendor notice yourself rather than trusting a summary, including this one.
• Figures are as reported by the original author and were not re-measured by us.

Details

Version 1.0 · Updated Oct 30, 2026 · Markdown version of this page
License: Personal and commercial use. Credit the original source when you share the workflow. Download terms

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