PUBLIC SAFETY WARNING!
Mac users who use the Transmission BitTorrent app to, um, legally download freely licensed content and shared software, take care: For the first time ever, a piece of "ransomware" has made its way onto the Mac platform. The KeRangers malware was included in a version of Transmission and it warns the user that the computer’s entire contents will be encrypted within three days, unless they pay a ransom of 1 Bitcoin ($3,177) into an anonymous account. Ouch. Transmission has since released a fixed version of its app, so upgrade if you can.