A well-meaning question on a mailing list asks for help with the following statement: “Unpatched systems represent the number one method of system compromise” This sentiment reflects static thinking, which ignores activity over time. When exploiting unpatched vulnerabilities no longer works, over time they will escalate to attacks that do work. In the case of targeted attacks, patching drives intruders to try other means of exploitation. We’ve been seeing that in spades over the last few months, even without widespread adoption of patches.”]
Source: https://taosecurity.blogspot.com/2012/09/over-time-intruders-improvise-adapt.html