Writeup for the Transformer challenge from VolgaCTF 2016 Quals

This is another challenge from the Volga CTF Quals 2016, involving an x64 ELF executable that encodes files. Our objective is to recover the clear text data from the encrypted file. Here’s the description for this challenge: This binary does something with the data. The transformation must be reversible, but the details are unknown. It shouldn’t be too difficult to reverse that transformation and obtain the flag, should it? [Read More]

Writeup for the Broken challenge from VolgaCTF 2016 Quals

This is a pretty nice challenge from the VolgaCTF 2016 Quals; sadly, I couldn’t join the r/OpenToAllCTFteam and play because I was too busy, but I noticed it was missing a writeup and decided to write one. The first thing I always do when I want to analyze an executable is to run it inside a disposable virtual machine; the first thing you will notice is that it doesn’t seem to be doing anything at all, and that it will closes itself after half a minute with the following message: “The processing has taken too long, terminating the process…”. [Read More]