Capture the Flag (CTF) competitions are hacking contests. The organisers write challenges based on some of the core domains of cyber security, ie. Cryptography, Reverse Engineering, Binary Exploitation, Web Exploitation and so on. These challenges vary in difficulty and accordingly are worth a different number of points if solved. Solving a challenge entails finding a 'flag', a short string that the challenge somehow conceals. The team to accrue the most points wins.
I got into CTF via my university society SIGINT at the start of my 3rd year of uni. They've proved fun and no end educational. Below are one or two challenges I enjoyed working on (nb. Still getting round to adding these!!).
pwnEd2 - easy_cheesy
This challenge was written by a friend of mine for a CTF that I helped run the first iteration of. I returned (remotely) to Edinburgh as a graduate to have a go at this challenge and one or two others. This was an introductory return oriented programming (ROP) challenge. Rewarding to solve as someone who sucks at binary exploitation.
