Anthropic hacked to deliver remote access trojan doublepulsar.com

Security researcher Kevin Beaumont reports that a malicious version of Anthropic’s Claude Code extension, version 2.1.313, was distributed through Cursor’s marketplace and attempted to install a persistent SSH backdoor; Cursor said about 5,000 systems were affected. The extension collected device information and tried to open a reverse SSH tunnel, though Cursor said errors meant the backdoor installation would usually fail without administrator privileges. Anthropic replaced the extension with version 2.1.314, which does not remove any backdoor already installed.