Malicious code in mcp-server-sequential-thinking (npm)

This threat involves a malicious npm package named 'mcp-server-sequential-thinking' that impersonates an official scoped package. The package.json includes a postinstall script and a binary entry that execute index.js automatically. The script collects system information such as hostname, current working directory, npm user-agent, Node.js version, and platform/architecture, then sends this data via an HTTP POST request to a Cloudflare Workers endpoint controlled by the attacker. The payload distinguishes between installation and execution triggers, confirming intent to harvest data through both mechanisms. The package targets developers and AI coding agents who mistakenly install or run the unscoped package. According to the source, any system with this package installed should be considered fully compromised.

Installation or execution of this package results in unauthorized exfiltration of system identifiers and environment data to an attacker-controlled endpoint. The compromise is severe enough that all secrets and keys stored on the affected machine should be considered exposed and require immediate rotation. The attacker may have gained full control of the system, and removal of the package alone does not guarantee elimination of all malicious artifacts.

No official patch or fix is available. Immediate removal of the malicious package is recommended. Additionally, all secrets and keys stored on the affected system should be rotated from a different, trusted machine. Due to the potential full compromise, a thorough security assessment and remediation of the affected system is advised. Users should avoid installing unscoped or suspicious packages and verify package authenticity before installation.