Major corporations spend hundreds of millions of dollars on protecting their systems from hackers and crackers, but they always forget one very vital thing: physical security. There will be a firewall hundreds of other security mechanisms, but you can walk up to a machine and put in a floppy disk and reboot, or just as easily gain access to the internals of the machine with a single screwdriver. If the machines contain trade secrets or sensitive data, just pull the hard drive, slip it into a briefcase and you could be millions richer. Or if you are willing to be more blatant, just put the entire system onto a cart and wheel it away, if you appear to know what you are doing, you will seldom be questioned or even given a second glance. Many security experts never think that someone trying to gain access to a system could possibly be within the building already, or be one of the users of the system for that matter. Here is one simple word of advice, secure your machines; bolt them down, lock them up, whatever it takes. | 
