About 50,000 music files were illegaly downloaded from the Sony Music servers by hackers. The files were the entirety of Michael Jackson's back catalog.
Among the files stolen were unheard studio sessions from some of his biggest albums, like Thriller, and Bad. There was also an unreleased collaboration with Will.I.Am.
The attack on Sony is just the latest it has suffered by hackers. Last year the Playstation Network was down for a period of time. This might be one of the costliest ones, though. Sony paid $250m for the catalog back in 2010.