The shadowx-fca npm package contains malicious code that intercepts Facebook login credentials. Its login function sends user email, password, and optional 2FA secret to a third-party server (https://minhdong.site) instead of Facebook, exposing sensitive data. This allows the attacker to obtain Facebook user IDs, access tokens, and cookies to impersonate accounts. The malicious behavior is present in versions 10.0.0 and 10.1.0 of the package.