This book will teach you exactly how hackers think so that you can protect your Unix and Linux systems from them. There is simply no other way to learn how to prevent your systems from being compromised. In order to stop the attacks of the most sophisticated hackers, you need to understand their thought processes, techniques, and tactics. The powerful nature of the Unix and Linux operating systems is a two-edged sword. In most cases, the operating system kernel source code is available for free, and an administrator can go so far as to change the operating system internals to suit his or her needs. But this powerful and flexible nature of Unix and Linux includes an enormous amount of complexity, which increases the likelihood of possible misconfigurations that can easily place a system at risk. Consider also the many different flavors of Unix and Linux distributions available today. Every distribution comes bundled with its own set of security policies and configurations. For example, some distributions leave a set of remote services turned off, while others turn on all possible services that have been configured with the weakest possible policies. Hackers are aware of the administrative complexities of managing Unix and Linux hosts, and they know exactly how to abuse them. This book will amaze you with details of the craftiest hacker tactics, and it will teach you how to defend against them.