I've had a few people contact me to ask about VAC bans, which hacks work and which don't. So I'll make a post for everyone.
As of today (21/02/2016 or 02/21/2016 if you're in America) only 3 hacks work which are undetected! There may be older ones which work, but they are probably detected. I use all these 3 hacks together and they work great and are undetected. In saying this, it doesn't mean you will not get VAC-ed or banned.
Please note the following hacks are NOT created by me! All credit goes to their rightful owners!
Working hacks
Mini tool 2.3 by eithan1231 & D3.-Starh<3
MW3 Multihack v1.2 by AuT03x3C
KevinTrainer by LillilateX, 191 & Nordiii