There was a Challenge Reset exploit that 15,000 players have used to amass large amounts of credit to the tune of 50,000 or so. Basically, the player could easily complete challenges over and over again by directly manipulating the network.
Hit the break to find out what Bungie is doing about it.
If you're one of the 15,000 Halo Reach players who blatantly abused the Challenge Reset exploit odds are you're going to be quite upset for being spanked like a a red-headed step-child by Bungie. I know what you're thinking and no, they did not ban anyone. That would be far too shameless. Instead they have decided to reset the credits the player earned all the way back to 0, zip, zilch, then notify them about it in the game with a one day credit ban just to make sure they know they've been served. Bungie also isn't content to stop there. Later this week they will be performing a more in-depth look into their player activity. For a Canadian company to come down so hard on cheaters makes me think the scum of the Halo universe might not be the Covenant after all.