One of the things any organization should be prepared for is a potential “incident”. The definition of incident can vary widely, but it can be anything from an unauthorized internal data access to a “hacker” breaking in.
Monitoring is a big part of detecting incidents and perhaps a post for another day. If you do suspect somebody has unauthorized access to one of your systems, though, there are certain steps that should be taken. I recently came across a good cheat sheet for server administrators that should be kept handy in the event of an incident. There’s also a cheatsheet for those responding to potential incidents.
I came across these cheatsheets over on the SANS Internet Storm Center blog, a good feed to have in your reader to keep up-to-date on the latest security incidents around the net.
Enjoy, and hopefully you won’t need to reach for these in the near future. But they are good to have on hand!