This really gets down to the infamous "Ten Immutable Laws of Security":
(http://www.microsoft.com/technet/columns/security/essays/10imlaws.asp)

And of course:

"The Ten Immutable Laws of Security Administration"
(http://www.microsoft.com/technet/columns/security/essays/10salaws.asp)

Note that these laws were not invented by or for a specific vendor or product, and have been in effect since the beginning of time. Well, computer-time at least.

Also note this article:

"XP Hole Plagues All Similar Apps"
(http://www.wired.com/news/infostructure/0,1377,57739,00.html)

Ruud