“People constantly discuss the issue of secure systems and often
get it wrong. Comments like “once an attacker has physical
access, your security is useless” are wrong because no security
measure will protect you 100% from all attacks.“
“Consider a server that is secure against network attacks by
being physically separated from any networks. Plus, all the
machines that can access it are similarly secured. The OS is secure
and the users are all vetted and non-hostile. This network resides
on the floor of an office building, with armed security guards and
multiple layers of physical access protection. The network has it’s
own UPS’s and generators, and all the machines are in heavy
hermetically sealed containers that are EMP hardened. Attacking
this network to steal data might be very difficult, but it is still
possible for an attacker to deny your access to it.”
“Security is never black and white – rather it’s one big ugly
shade of gray. A machine running ancient software with poor
passwords that is physically secured and not attached to any
networks can be far more secure then an up to date machine with all
the latest security software, on a public network. Security is
about risk management. Are you willing to risk an elite commando
unit of trained sysadmins breaking into your building at 3 a.m. to
steal your data? Most people probably are, since the chances of
this happening are slim and the cost of protection is high. On the
other hand, if you want to prevent someone from breaking into your
mail server via the Internet, a reasonably common occurrence, then
investing in a firewall and keeping software up to date is probably
a cost effective strategy.”