In 2011, computer and network security news stories, which were previously the preserve of specialist journals and blogs, have become commonplace in the mainstream media. There are now many different types of threat, which are sometimes categorised into hacktivist, e-crime and most recently, advanced persistent threats (APT). Whilst some of these attacks have exploited zero day vulnerabilities, many of these attacks have simply taken advantage of the fact that systems have not been configured securely for their deployment environment.
To use an easy–to-understand analogy, consider a wireless router. This device will generally be shipped from the factory in the most flexible, open communication configuration, which will have many or all of the security options disabled. This will be fine if the wireless router is intended to be used as a free public Wi-Fi access point (e.g., cyber cafe), but not for a private business or home office if you want to prevent drive-by wireless hacks). In these cases, wireless encryption such as WPA2 will need to be enabled for the router and clients, and access may even need to be restricted to specific clients via MAC addresses, etc.