Defcon Capture the Flag: defending vulnerable code from intense attack

Defcon´s Capture the Flag (CtF) game is the largest open computer security hacking game. This year´s CtF had rules that made it particularly difficult to be a successful defender. We entered an Immunix server, comprised of five years of IA and S, OASIS, FTN, and CHATS technologies, to see whether this system could survive sustained attack from determined experts. We describe our experience surviving Defcon CtF.