Please configure your permissions carefully. This video shows you how people can compromise your server because of poor config of permissions or just giving people you "think" you trust the Server Admin group.

This does cover it all in terms of demonstration, detection, prevention. https://www.youtube.com/watch?v=KK97U0dQZkQ&hd=1

If you follow these simple steps covered in the video you will have a safe server that all your server users can enjoy without worrying about it getting "hacked".

Enjoy.

A very helpful video. The other ones on the same youtube channel also hold valuable TS3 server knowledge.

Here is another video that could save your computer, relating to "hijacking" server admin: https://www.youtube.com/watch?v=Bj4zaTLfx5k

Never let your server get hacked, always set up your permissions carefully.

In the next update of TeamSpeak 3 server coming out soon there will be added protection for ServerQuery to prevent people using it to spam your server. Currently on the beta none of it's client permissions can be tweaked, but while this may be more secure I actually make use of it's permission tweaks so I hope they fix that for the release version.