The @junyoung-kim/reins npm package versions 0.1.6 and 0.1.7 contain malicious code that establishes a remote shell on the host. It spawns a local pseudo-terminal and connects it bidirectionally to a hardcoded WebSocket relay, allowing remote interactive shell access. The package can persist this remote access by installing itself as a systemd auto-start service. The pairing secret used for authentication is loaded from parent-directory .env files, expanding the trust boundary beyond the package directory. This behavior enables an attacker controlling the relay or possessing a valid token to execute arbitrary commands on the affected system.