MMO with Hackable Currency?

I'm looking for a MMO where the in-game currency is moddable/hackable I don't care about trainers or anything. Or if there is an easy way to exploit the game and make a ton of cash that would be helpful too. Thanks in advance!

Its theoretically possible in most MMOs, but you'll likely have to find it yourself, I wouldn't count on anyone making a major exploit like that public.

I remember a few from the good old days of hacking Maple story. One was sending a custom packet to donate negative max meso to an NPC. Another involved trading items to another user, having them log out and then crashing the server you are still logged into before it finished updating the DB creating a dupe. A third involved editing a game file to remove text of a Christmas NPC who would give you 10 meso when you started that Christmas quest. Then you would automate starting and forefiting the quest as quick as you could.

If you watch the Defcon video DEFCON 19: Hacking MMORPGs for Fun and Mostly Profit the speakers talk about another game where you could send modified packets to have an NPC initiate a trade with you, then you could take whatever rare items out of their inventory you wanted.

No idea right now, not that I'd tell you if I was exploiting any for money... You'll pretty much have to find something on your own by learning more about hacking.