
Backdoor in Claude Code for VS Code extension on the Cursor Marketplace
Phorion analyzes a backdoor injected into versions 2.1.312 and 2.1.313 of the official Claude Code for VS Code extension on the Cursor Marketplace. An IIFE prepended to extension.js plants an SSH key, opens a reverse SSH tunnel to 134.209.82[.]225, persists via a fake com.apple.sysmond LaunchAgent and beacons host recon. A macOS systemsetup check bug usually stops SSH from being enabled. The post lists detections and remediation.
Supply Chain, Malware & RE, Blue Team & DetectionΒ· Added 31 Oct 2026, published 30 Oct 2026












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