The rule is: If you can access the machine you can hack the machine. If you want security the machine needs to be completely unaccessible, secondly it needs a BIOS password and the BIOS should be set so that the box will not boot from cd or floppy. Yes, Knoppix makes it unbelievably easy to do but it is not really anything new. Why would you hack your own employers server and write about it in a forum though?