Technology
Backdoored Anthropic extension may have exposed thousands of developers through Cursor
A malicious version of Anthropic’s official Claude extension for Cursor was available for several hours and may have reached as many as 5,000 users. Cursor said it installed a persistent SSH backdoor, added an attacker-controlled key and opened a reverse tunnel, potentially exposing files, source code and development tools on Windows, macOS and Linux. Anthropic released a replacement version, but neither company has explained how the account was compromised, and Anthropic had not publicly warned customers when reported.
Editorial summary · Publisher article
What matters
- The affected package was version 2.1.313, later replaced by version 2.1.314.
- The extension could auto-update and ran with the permissions of Cursor’s integrated development environment.
- Researchers said the attacker controlled Anthropic’s official distribution channel on Cursor.
Context & caveats
- The reported maximum of 5,000 affected users and the attribution of the compromise remain subject to further investigation.
Why this made the edition
A well-supported supply-chain compromise affected an official distribution channel and potentially exposed developers across major operating systems. The technical mechanism and customer-notification gap are both consequential.
Source material