Plug: I've been building Packj [1] to address exactly this problem. You can _audit_ as well as _sandbox_ installation of PyPI/NPM/Rubygems packages and flags hidden malware or "risky” code behavior such as spawning of shell, use of SSH keys, and mismatch of GitHub code vs packaged code (provenance).

1. https://github.com/ossillate-inc/packj flags malicious/risky packages.