DiracX-Web is vulnerable to attack through an Open Redirect on its login page

Summary

An attacker can forge a request to redirect an authenticated user to any arbitrary website.

Details

On the login page, we have a redirect field which is the location where the server will redirect the user. This URI is not verified, and can be an arbitrary URI.

Paired with a parameter pollution, we can hide our malicious URI (ex: https://dns.com/?param1=im_hidden_if_theres_lot_of_args?param1=bbb).

PoC

https://diracx-cert.app.cern.ch/auth?redirect=https://ipcim.com/en/where/?dsdsd=qsqsfsjfnsfniizaeiaapzqlalkqkaizqqijsjaopmqmxna?redirect=https://diracx-cert-app.cern.ch/auth

This POC can leak user's position.

Impact

This could be used for phishing and extracting new data (such as redirecting to a new "log in" page, and asking users to reenter credentials).