Rcon Hacking

Hello, I am willing to gift any game on steam (i buy game and give it to you as gift) only if someone could teach me how to hack Garry's Mod server Rcon's. I know this is possible because this happened to my server. Every one who joined became super admin and i could do nothing and I am only person who can do that. I couldn't do anything about it as I did not know who it was. All I want is to know how to do this to other servers to make my self admin. If any one is interested please pm, comment here or add me on steam.

Steam: (SG)Savage

what is your server?

I shut my server down as every one who did play on it was admin and the hacker kept making every one admin.