First you must have 2 people to do this glitch on zombies.

Have the first person go to the wall with the M1A1 Carbine and lay down on the ground by the crates.

Crawl forward a few inches. Next the second person runs and jumps on top of the person laying down.

Make sure the arrow that says where the team mate is at is pointing straight up.

Next the person on top walks towards the crate and wall as the person on bottom stands up.

Now neither person must knife, throw granades, or touch the left joystick.

The zombies can't touch you!

To get out of the cheat just walk any direction.