This is my writeup for byhd, a 2-point challenge from the Defcon Qualifier CTF. You can get the files, including my annotated assembly file, here. This is my second (and final) writeup for the Defcon Qualifiers, you can find the writeup for shitsco here.
This was a reverse engineering challenge where code would be constructed based on your input, then executed. You had to figure out the exact right input to generate a payload that would give you access to the server (so, in a way, there was some exploitation involved).
Up till now, cnot from PlaidCTF has probably been my favourite hardcore reversing level, but I think this level has taken over. It was super fun!Continue reading