The anticipated Xbox 360 shooter has found its way to numerous file-sharing sites after at least one person illegally uploaded the entire game to the Web.
The game file is around six gigabytes and can be transferred to and played on illegally modified consoles, reports GamesIndustry.biz. It has reportedly been uploaded within the past 24 hours.
Halo 3 is slated for a September 25 release date, and it is unknown who the source of the download is. Earlier this week, UK store Argos began selling copies of the game several days in advance but has since stopped.
The Xbox 360 title, which has already received more than a million pre-orders, is backed with a huge promotional campaign that some are calling the most extensive of its kind for a video game.