Okay, let me try to explain this if I'm correct. The hacker asks me to join their server. As I join, my account AUTOMATICALLY does some check to make sure my account is legit. The server asks my account for a number, and my accoutn automatically responds with the number. The hacker intecepts the number so he gets it instead of the server. Now the hacker has my unique number, and when he sends THAT number to a server, the server will think "OH! You're number 1123! That's Paradox's number!" and log him as me.