There's been a new bullshit update that came out. It only updated the exe file. Even though its technically the same version, it messed up all the cheats made for that version. Unfortunatly now all the good hack devs are gone (probably making hacks for the new COD games). Now we're left with amature coders that makes crashy almost non functioning hacks. The best one that works so far is MW3 Multihack v1.1 by AuT03x3C.
But make sure to start the game and be in a match already before you start the hack. Otherwise it will crash. The only function that works on that hack is the UAV. The rest won't work.