An interesting article by my friend Mauricio, and a timely warning
Operating System security is [only] as good as the admins
http://www.geekzone.co.nz/freitasm/3578
"This last week, 5 of the 8 servers that are loco hosted but Canonical sponsored, had to be shut down due to reports that they were actively attacking other machines. These servers were found to have a variety of problems including, but not limited to, missing security patches, FTP (not sftp, without SSL) was being used to access the machines, and no upgrades past breezy due to problems with the network cards and later kernels."