you can get a form on line "hacks" two of...

1) online vault hacks some of which will in a online lobby but you will need a lag switch.. if not most of them if made correctly will work in a private match..

2) a friend with a jailbroken or DEX ps3 can hack your ps3 for you.. but only to a certain stage... eg.. MW3 you will be able to get the "GODMODE" or invisible class but will not get wall hacks and aim bots ect because you need to install CFW which is only able to be used on DEX consoles..

im new hope this helps