Ban hack?

Is there a hack or mod that exists that can let you ban someone from a server even if you have no command permissions? I was banned from a server I moderate by a GUEST. He came on and said "Are you the server owner?" I replied "No, I'm the moderator" then he said "You want to see something?" After teleporting to him I was quickly disconnected and was staring at "You are banned from this server!"

WTF!? How is this possible? It was not the server owner or an admin. It was a player I've never seen with no build rights. I wont' see the server owner till later today as he has school.

Anyone know how to prevent people from doing this? Or how to prevent the use of mods all together? If you know how he done this and dont' want to let other's know Please PM me.

The player's name was Skelsteel.

I believe there used to be some kind of glitch with the names that allowed you to have admin powers just by changing your name.

Like derp said the admin files are name based which is why me and Dead switched to mineshafter since in offline mode, people can login with whatever name they want, an admins name for admin powers, op name for op powers and so on.