Every year at Defcon they assemble a huge computer network and populate it with machines of all kinds as part of a competition. The objective is simple: Crack as many of the system on the network as you can, find the flag (it's a Capture the Flag competition), and defend your turf as best you can. The game requires the competitors to think fast on their feet because they don't know what they'll run into on the CtF network, and they'll be faced with network services that they may never have seen before. The challenge is to find vulnerabilities in …