Hundreds of game pirates have inadvertently given over their computers to Bitcoin miners when they downloaded "Repacks" of infected games.

Microsoft has identified dozens of game torrents that are malicious. Donna Sibangan, of Redmond's Malware Protection Centre's, said the infected torrent listings (to which the .torrent files relate) were listed as 'repacks' - pirate vernacular for a torrent upload that corrected errors in a previous listing.

Sibangan said: "These files can be easily acquired by anyone who downloads games from a torrent website. The games are repacked to further lure gamers to download the compressed files for free."

Infected torrent listings included the deluxe edition of WatchDogs, Don't Starve, and the premium edition of King's Bounty: Dark Side, all released under the name 'Deception', and two versions of Tom Clancy's Ghost Recon: Future Soldier. The dropper detected as TrojanDropper:Win32/Maener.A was executed when the setup.exe installer was run and fetched the Bitcoin miner.