A massive error by Microsoft's Xbox team resulted in the leak of the recent Gears of War 3 build to torrents. According to PS3 hacker Mathieulh, and the offending sections of the website that hosted the developer build of Gears of War 3 have been taken offline, but as Google cache reveals the pages were indeed there at some point (see second pic below).
The first cached page shows a ftp directory located on xbox.codify.com marked "/GOW3/GEARS-OF-WAR-3-CONFIDENTIAL/", and subsequent directories, such as the one cached, included the game's content.
The second cached page shows game assets; all directories seemed to be accessible without any sort of password, encryption or other security method in place.
Codify, hosts of xbox.codify.com where the GOW3 build was found, offer "software engineering and managed hosting." They appear to be an Australian-based company and on their website front page there is a testimonial from a Microsoft manager, which indicates that the company does deal with Microsoft in some capacity. We dug deeper to see if Microsoft was the actual source of the leak.
Codify's director said that they simply hosted a server for the Xbox team at Microsoft, which further points to Microsoft accidentally leaking their own game. They said they would follow this up with Microsoft.