auth0/node-jws Improperly Verifies HMAC Signature

Overview

An improper signature verification vulnerability exists when using auth0/node-jws with the HS256 algorithm under specific conditions.

Am I Affected?

You are affected by this vulnerability if you meet all of the following preconditions:

1. Application uses the auth0/node-jws implementation of JSON Web Signatures, versions <=3.2.2 || 4.0.0
2. Application uses the jws.createVerify() function for HMAC algorithms
3. Application uses user-provided data from the JSON Web Signature Protected Header or Payload in the HMAC secret lookup routines

You are NOT affected by this vulnerability if you meet any of the following preconditions:

1. Application uses the jws.verify() interface (note: auth0/node-jsonwebtoken users fall into this category and are therefore NOT affected by this vulnerability)
2. Application uses only asymmetric algorithms (e.g. RS256)
3. Application doesn’t use user-provided data from the JSON Web Signature Protected Header or Payload in the HMAC secret lookup routines

Fix

Upgrade auth0/node-jws version to version 3.2.3 or 4.0.1

Acknowledgement

Okta would like to thank Félix Charette for discovering this vulnerability.