How do hackers...

Hello,

I’m still pretty new the whole “Server Admin” thing, and I was wondering...
What are the most common techniques that hackers use today?
-allow me to explain:
I’d like to see some of the Admins(Any Admin, Win - *nix) on AO explain/list the more common attacks they see in their logs. Oh yeah, I’d rather not see any script kiddies post exploits, that’s not the point of this thread, I really want to get a clear grasp of the problems / issues / signs I should be looking for, protecting against, etc...

Thanks,
Hopefully this thread will be informative ;-)