Microsoft spokesman Joe DIMiero told Polygon yesterday that the company is working closely with their security teams and law enforcement to investigate the apparent theft.
Polygon caught up with developer 343 Industries at New York Comic Con as they prepared for their Halo 4 panel set for later today.
Frank O'Connor, Halo franchise director, said that Microsoft was aware of the apparent torrents of the game that are now online and of the videos showing the campaign.
"There are people putting the whole thing on YouTube," he said. "Microsoft is addressing that a single case at a time, it just takes a little while to handle."
O'Connor said the leaks of the game and footage won't have any impact on how the game is released or marketed, including today's planned talk on the game at Comic Con.
The entire team seem unfazed by the leak of the game, rumored to have come from a production facility.
"This is how surprised I am about this," O'Connor said as he shrugged slightly, adding that piracy of high-profile games is sort of inevitable.
Halo 4 is currently scheduled for a release date of Nov. 6.