"Player" Logging in/ help with anti hacking mods

My new server is doing great except for the fact that people are complaining about others using mods. People can log in with the name "player". This is from my friend that i copied his bukkit file from made it so free clients could log in. I need to know how to disable this asap.
As i am new i need to know some ant-hacking clients. I don't use permissions atm but have essentials, factions, and mcmmo. I do have RawcriticsOreObfuscationPluginSpout as an anti x-ray mod. I need an anti-flying mod too as someone flew on the server. Please help me i need to fix this before a lot of players leave.
Thx for all the help

 

Antiflying mod, (NoCheat)... Players who can log in with "player", seem only to be possible if you got the server in offline mode which you probably dont got. So it would be a hacked client...
Also if you need something against some hacked clients, you can add SpamGuard, if someone use a spam mod they will be kicked and banned...

 

Thanks a lot for the help! I installed SpamGuard and NoCheat and now players can't fly! The cleaner chat is also a plus. Thanks a lot.