Austin Wilson of the Windows Vista Security Team reported back from the recent Black Hat conference about a demonstration in which a security researcher inserted unsigned code into the kernel of an x64 version of Windows Vista. This demonstration has led many to declare the security of the upcoming Microsoft product to be poor.
Of course the person running the demo had administrative rights to the computer to begin with. Austin says it pretty well:
“There is no “silver bullet” when it comes to security, and it’s very difficult to protect against an attacker that is sitting at the console of your computer with an administrator command window open.”
In essence this demonstration only proved that an operating system is not impervious to the actions of a person who has full administrative access to the computer. Just think what a person can do to a Linux or BSD computer with root access.