Anthropic denies breach as tampered Claude Code extension hits Cursor users
Comments
Ranked by a public rubric, not by votes: what a comment adds counts, not who wrote it. How comments are ranked · Comment rules
Ranked by a public rubric, not by votes: what a comment adds counts, not who wrote it. How comments are ranked · Comment rules
Summary
Cursor said tampered versions 2.1.312 and 2.1.313 of the Claude Code extension were live in its marketplace for about 11 hours on 29 October, reaching up to 5,000 users. The code tried to add an attacker's SSH key, enable SSH and upload machine details and the names of secret-like environment variables. Anthropic says its systems were not breached; Phorion says the upload used Anthropic's official account. How the attacker got access is unstated. Auto-updating extensions are a supply-chain risk, and uninstalling may not remove the backdoor.