closure-util downloads Resources over HTTP

Affected versions of closure-util insecurely download an executable over an unencrypted HTTP connection.

In scenarios where an attacker has a privileged network position, it is possible to intercept the response and replace the executable with a malicious one, resulting in code execution on the system running closure-util.

Recommendation

To mitigate this issue:

1. Install the package using npm's --ignore-scripts flag.
2. Navigate to the package directory, and open default-config.json in a text editor
3. Change the download URLs in the compiler_url and library_url to https equivalents
4. run npm i in the package directory.