Anthropic was compromised in a supply chain attack, with the Cursor VS Code extension for Claude access delivering a remote access trojan (RAT) via an SSH reverse backdoor. The malicious version, 2.1.313, auto-updated to tens of millions of developers using Cursor. Around 5000 developer systems were impacted.
Phorion was the first to detect the malicious activity. Anthropic silently replaced the compromised version with 2.1.314 eight hours later, without informing customers. While the new version removes the backdoor from the extension, it does not remove the SSH backdoor from already-infected systems.
The malware collects host and user information, attempts to add an attacker-controlled SSH key, and creates a persistent reverse SSH tunnel. It reports status via HTTP POST to port 8099. Notable affected customers include Binance.
The attack used the IP 134.209.82.225 for command and control. The extension was uploaded through Anthropic's verified account, raising concerns about the security incident response.
Source: Hacker News · Summarized by HeadlinesBriefing