CyberChef VIII

Challenge description:

Can you find the flag in this?

{
  "user": "backup",
  "id": "p5FF8sb6-tGL7-k179-tVuG-VhidzbGjANzt",
  "checksum": "==QfIdWa51kWBlFSwl2NvhlY3hFV"
}

Alright, this is a two-parter with some misdirection. First, lets look at each of the sections in the JSON. Funnily enough, for as difficult as this challenge may seem, iits just a few different types of bases obfuscated.

The first thing we had to do was realize that the checksum, was just some Base 64 backwards. So first we pull out the reverse block, and then the From Base64 block. and we now have the following: TXwbXo7ipHYAZMyigH}

Seeing the end bracket there, probably means that that’s the end of the flag, lets look at the id string to try and get the first half.

Now, with this first half, given that the “checksum” was most definitely not a checksum, its probably safe to assume that the id isn’t actually a UUID. So let’s go ahead and remove all of the dashes, and see what CyberChef thinks of the remaining output.

Well I’ll be damned (She says as if she didn’t make the challenge). It looks like CyberChef was able to figure out that all out needed after the replacement was a From Base58, and got out the beginning of the flag.

Combine the two parts, and you’ve got it!

FLAG: STOUTCTF{FcjebVn495CQJaTXwbXo7ipHYAZMyigH}