The Web site that hosts uTorrent was hacked by an unknown person or group early this morning. After initially stating that the "mainline" BitTorrent site had been hacked as well, the company now says that it doesn't think that BitTorrent.com was affected. BitTorrent, the owner of the Web sites and the torrent clients hosted there, reported in a blog post that the breach occurred around 4:20 a.m PT.
According to the blog, the proper executable files for both programs were replaced with "a fake antivirus 'scareware' program" called Security Shield. The company shut off the download spigot at around 6 a.m. and has since restored the proper download files. BitTorrent advises that anybody who downloaded the programs between 4:20 a.m. and 6:10 a.m. PT runs a security scan.
Removing fake antivirus programs, which are almost always a kind of rootkit, can be notoriously tricky. It's advisable to start with Malwarebytes Anti-Malware (before panicking) to determine if there actually is an infection.