CrossCTF 2017 Writeup

Where to begin? Well, I guess I'll begin right at the start before I even decided to join this competition. 2-3 months back before we even had the qualifiers, I tried to join CDDC 2017 but was rejected with an excuse of too many participants, so I turned to CrossCTF for my salvation.

Preliminiaries was marginally fun, with challenges from all categories and incorporating various techniques and vulnerabilities that I had not even heard of till this CTF, like SHA-256 collision. I learnt a lot and during those 48 hours, I tried my very best to bring my team up so we would qualify for the finals. As such, we came in 4th place, with the only uncompleted challenge being LeapFrog.

Finals was intensely hard and difficult. Two contributing factors to that is the full-binary nature of it, coupled with the 24-hour marathon-style of the competition, so I had to deal with both binary, my weakest CTF category as well as the lack of sleep. Nevertheless, I tried my best and managed to secure the 7th place at 12pm, tieing in place with the 5th and 6th team from Nanyang Polytechnic.

Learnt much, got much to learn.