This achievement is done on the Zombie map Moon. If you don't have moon you have to buy the map pack Rezzurection. What you do is you go through all the doors that lead to the power room which cost 3750 points if you go through tunnel 11 or tunnel 6 correct me if I;m wrong. Next there will be a door next to the power room. Open that door and look on the tables there should be a hacker device on the table. You only HAVE to hack ONE thing. There are many things to hack here's a list
Hack gun off the wall cost: 3000 points
Hack a power up cost: 5000 points (it will give you a max ammo)
Hack excavator (digger thing) cost: Free
Hack pack a punch machine cost: Free
Hack a door cost: 200 points (takes 30 seconds best if you have a crawler)
Hack a switch for the Easter Egg cost: Free
Hack the mystery box cost: 1250 points
Hack a perk machine cost: You get a full refund on the perk you bought
If i missed anything else you can hack leave a comment telling what I missed but I'm pretty sure that's all