What Happened
A trojanized build of Anthropic’s official Claude Code extension reached the Cursor Marketplace on October 29, according to The Hacker News. Version 2.1.313 of the anthropic.claude-code extension carried a 66-line loader ahead of the legitimate code. After the editor started and a webview opened, the loader added an attacker SSH key labeled svc-telemetry to authorized_keys and opened a reverse tunnel to 134.209.82.225. It installed persistence through a scheduled task, crontab, or LaunchAgent. It also sent host details and the names of up to 40 environment variables to the attacker over unencrypted HTTP.
Cursor says at most 5,000 users installed the build between 2:27 a.m. and 1:35 p.m. PT. Anthropic published clean version 2.1.314, and Cursor briefly shut down its marketplace to remove the bad build. How the attackers pushed the update remains unclear.
Why This Matters for Canadian Organizations
Canadian software shops, banks, and public sector teams run AI coding assistants inside editors with access to source code, cloud keys, and internal networks. An SSH key in authorized_keys gives an attacker quiet, lasting access long after the extension updates. Developer laptops sit beside production credentials, so one infected machine exposes customer data held under PIPEDA. Financial institutions under OSFI Guideline B-13 also answer for third-party software risk, and an editor extension is third-party code.
The incident follows the OVHcloud CLI compromise earlier this month. Attackers now target the tools developers trust most. Our TechTalk coverage tracks this pattern.
What to Do
Find every machine running Cursor with version 2.1.313 on October 29. Inspect authorized_keys for the svc-telemetry key and remove it. Look for new scheduled tasks, crontab entries, and LaunchAgents. Block outbound traffic to 134.209.82.225. Isolate affected hosts and rotate credentials and sessions, starting with any environment variables holding keys, tokens, or secrets. Pin extension versions for security-sensitive tooling and review marketplace updates before rollout. Follow our latest news coverage for updates.
