To run a mod menu on CoD Ghost, you need a 3.55 CFW PS3 with DEX firmware on it in order to RTE (Real time edit) Ghost. There isn't any protection to be ban so I advise not to mod newer games, but mod older games as it's safe.

If you ever plan on downgrading your PS3, make sure you've bought your PS3 before 2010 and use a E3 flasher to downgrade :p.

You can not mod without a CFW on Ghost, so I advise to buy a CFW PS3 or just downgrade your PS3.

Exactly what Joelrca said, or you can go on eBay and get your PS3 downgraded there. There are a couple of high quality services on there and it doesn't cost as much as a E3 flasher. But I suggest you do some research before getting your PS3 downgraded. Here are some threads you can look at:
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and here is an explanation about some of the stuff like : DEX, CFW and so on:
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