For those of you that missed it last time, CryptOMG is a configurable CTF-style test bed that highlights flaws in cryptographic implementations. The application and installation instructions can be downloaded for free at the SpiderLabs Github. The challenge 1 walkthrough can be found here.
The goal for the second challenge is to get the admin password. Unlike the first challenge, which told us there was probably a directory traversal flaw, this does not give us a very clear picture of the type of flaw we will be exploiting. After opening the application, we are presented with a login form and instructions telling us that we can login with guest/guest. Taking a closer look at the URL parameters, we have a "ReturnUrl" parameter with 32 hex characters, in this case 82803ac0ee614d894128649a2eb31f03.