What is this new Modern Warfare 2 hack?

i recently went back to play a little mw2 after becoming a bit bored with black ops. i found that more than not i was getting into hacked lobbies. when one of the hosts kills me and i watch the killcam it shows him as having some sort of hack menu where he can choose what he wants to do like teleport or god mode or stuff with harriers and whatnot. also he can change my clan tag and make it colors and stuff and sometimes ill get into a match and it will say "match by..." and have somebodys gamer tag in there. another thing is the host who has done this hack can end the match whenever and change the level and turn the hacks on for some people and not for others. i would like to know where this hack came from and how can i get ahold of a download for it...