r4wk-book @2.2.2

Summary

On npm install, the package's postinstall hook runs node.worker.js , which detaches a background child, waits a jittered delay, and opens a TCP socket to a base64-encoded host:port literal that decodes to 172.16.42.138:1234. It then spawns /bin/sh -i (or cmd.exe on Windows) and pipes the socket to the shell's stdin and the shell's stdout back to the socket, giving whoever controls that address an interactive shell on the installer's machine. The destination is stored as Buffer.from('MTcyLjE2LjQyLjEzODoxMjM0Cg==','base64').toString().split(':') rather than a plain literal, concealing the endpoint. The package.json advertises a generic purpose ("Background sync module for legacy systems") and declares itself as its own dependency ( r4wk-book: ^2.2.1 ), consistent with a throwaway lure rather than a functional library.

Source: amazon-inspector (7f5cbca68751eb879140f7c896a0dc3c324e9f4dbc8a1651b38b246b299ba4eb)