Over the weekend, pirates uploaded leaked copies of Microsoft’s Halo 4 to several peer-to-peer distribution sites.

Microsoft and developer 343 Industries debut their sci-fi first-person shooter on Nov. 6 exclusively for the Xb0x 360, but those of nefarious means have already begun downloading and playing the anticipated game weeks before that official launch. The publisher isn’t happy about this.

Microsoft provided GamesBeat with the following statement:

We are aware of isolated cases in which “Halo 4” content has been propped on the Web and are working closely with our security teams and law enforcement to address the situation immediately.

Consumers should be aware that piracy is illegal and we take vigorous action against illegal activity related to our products and services. Playing pirated copies of games, such as Halo 4, is a violation of the Xbox Live Terms of Use and will result in enforcement action, such as account and console bans.

In terms of account bans, we’ve confirmed with Microsoft that the following image of the Xbox Live enforcement team permanently banning someone’s account for “prerelease title play” is authentic:

The comments section on an infamous site for torrents  (a special file for downloading content, often illegally) is filled with users announcing that they’ve been banned. Users are warning others not to play the game.

The Halo 4 leak is a 16 GB file with two DVDs worth of data. Over 400 people have already downloaded it from the previously mentioned site, while another 2,500 are waiting for their download to finish. The game’s entire single-player campaign is available on the first disc. The second DVD’s info includes the install information for Halo 4’s multiplayer.

Microsoft is investigating how this leak happened.