As video game playing has become a professional sport that attracts large audiences and winners can receive cash prizes, gaming companies see cheaters and game hack software as big threats to their bottom line. Gaming companies are fighting back by hiring spies and developing new software to identify and prevent cheaters.

Activision Blizzard, the maker of games like Call of Duty and Overwatch, and e-sports contest organizer ESL are currently spending hundreds of thousands of dollars annually on software and new employees to combat cheaters. But the companies expect these costs to rise next year, the Wall Street Journal reports, as the problem of cheating worsens.

"It's an arms race," Jeff Kaplan, director of multi-player shooter game Overwatch, tells WSJ. Within a week of Overwatch's release, the company banned thousands of players for using cheat programs to enhance their in-game abilities. Other games, like League of Legends, are also banning thousands of cheaters. Last month, Overwatch hired its first full-time engineer whose sole job is to fight cheating. Video game companies are also deploying spies find cheat codes and software vulnerabilities.

Cybersecurity company Panopticon Laboratories estimates that players around the world spend between $350 million and $500 million a year on cheat software, WSJ reports.

Riot Games, which is the maker of popular game League of Legends, sued LeagueSharp, a Peruvian company that offers a subscription service for game hacks. Riot Games, in its complaint, said LeagueSharp was causing permanent damage to the League of Legends player community. In early March, a court ruled that LeagueSharp was to shut down and give Riot Games $10 million.