A free-to-play game named PirateFi in the Steam store has been distributing the Vidar infostealing malware to unsuspecting users.
Valve has added a new security layer for developers who publish their games on Steam after a few had their accounts hacked.
Valve fixed an exploit cheaters were used, and used that patch to catch them in the act. More than 40,000 people were banned for using the third-party cheat.