Software that can see opponents through walls. Aimbots that can lock onto other players automatically. Tools that can boost characters’ stats to the max. The world of online game cheats is expansive—with some cheat websites advertising hacks for dozens of PC games—and it’s being driven by an underground economy that’s allegedly raking in millions every year.Over the last two years, a group of computer scientists has been analyzing and mapping the online cheat marketplace, observing what behavior...