Peter Eastgate of Denmark after winning $9.15 million during the World Series of Poker at the Rio Hotel and Casino in Las Vegas in 2008. REUTERS/Steve Marcus Hackers have found a way to cheat at online poker by using malware to take screenshots of the cards players are holding.

A report from ESET (via The Register) said the practice had affected hundreds of players on poker websites such as PokerStars and Full Tilt Poker.

The malware infects a player's computer, takes a screenshot of his or her hand of cards, and then sends the unique ID of the player to the hacker. From here, the hacker can find the player in the online poker rooms and play against the person with knowledge of the person's hand.

ESET has been detecting the malware since March in various forms. Newer versions of the malware have are better able to access other parts of the computer as well, such as passwords.

While hacking online poker tournaments is rare, it is far from unprecedented, and there is very little that online poker companies can do to prevent it, as the malware is usually contracted from an outside source, such as a torrent download.