Question:How does Hacking work... and How are they fixed? (The technical stuff)

For the "fixed" portion, does just prevent access to the command that allows you to hack, or do you change the codes so that if it was attempted, it would instantly fix itself or render the hack ineffective?

I know hacking is putting in commands/codes in, but what does it actually do? Make the program do what you want, or just basically injects things in that isn't usually there?

This is just my curiosity, but I would like to see people's replies

Also, apparently i know some people who have been taking advantage of the hackers, and buying their items because its usually underpriced(for example, Dark crest helms usually at 4 mil[East], were sold by hackers at 1.7 mil, then my "friends" sold them at 2 mil-2.5 mil), and selling it for a higher price. Wierd eh?

Quick rundown on fixing commands. If a command is a dev command, you have ot have dev permissions to use that command. Impossible to get dev commands with public methods. When they fix commands, they add dev protection to them. Ta-da.