Second time this has happened now, and I know those who use a Mac and BitTorrent, tend to use Transmission as their client.
The malware, dubbed OSX/Keydnap, is pretty nasty. It’s designed to steal the contents of the OS X system keychain and maintain a permanent backdoor. And for a few hours, that malware found its way into the popular Mac BitTorrent client, Transmission.
The good news is that “within minutes” of being notified that a rogue version of Transmission was discovered, the Transmission team removed the file from its web server. The bad news is that it’s unclear how long the rogue version of Transmission was available or how many people could have downloaded the file.
Is your Mac infected? Check using the details in the first post.