Source -A game of chess is a simple analogy for software security efforts. Opponents move one at a time, and, as a general rule, one of them is at least a step ahead. There’s a continuous, silent race between hackers and software developers, the first seeking to break protections built into products, the latter aiming to bulletproof solutions as much as possible, in order to conserve that “step ahead” advantage and protect customers. This is valid for products such as Windows 7 and Internet Explorer 8, considered at the top of their game in terms of the level of security they deliver, especially after being built with the help of the Security Development Lifecycle.
Windows 7, No Security Barriers, Just Defense in Depth Mitigations - Protecting users is a top priority, says Pete LePage - Softpedia