Professional Windows Server 1002003 Security A Technical Reference [Electronic resources] نسخه متنی

Principle Number One: There Is No Such Thing as a Secure Computer

This should be evident to most people in computing. By now, every operating system, browser, or application that is exposed to the Internet has been taken to task by malware or attacks perpetrated by using some feature or bug in the product. Like life, computing poses risks depending on what we do, where we are, when we do it, how we do it, and perhaps even why we do it. Our job in information security is to correctly gauge that risk and do what can be done to mitigate it. At the same time, we have to keep in mind that there is no such thing as a secure computer. Computers are more or less securable, though, and the security of the information stored on them (or transferred by them to other computers) depends on how well we understand how to secure them.

Securing computers is a process that is part hardening, part auditing to make sure we did it in the best manner and that configuration stays in place, and part intrusion detection and response. But "securing" is not a process that makes computers secure. Instead, it must be defined as a process that makes a computer as secure as possible, given current knowledge of the threats that the computer will face.

Perhaps a better way to think about security is not as some unattainable goal, but as a continuum. On one end is a computer system that has a poor security design, that has had no hardening, that has non-existent external defenses, and that is used by individuals who purposely practice "unsafe" computing. On the other end is a computer designed by the most knowledgeable security engineers and uncluttered by any marketing requirements to make it user-friendly or to conform to some standard other than security. This computer also has been hardened (there will always be some post-design flexibility that requires that the computer be used for something). The computer has multiple external defenses including firewalls, anti-spam, anti-virus, and anti-spyware perimeter controls, in addition to network access controls, which include security requirements that must be met before a computer can operate on the network. The computer is operated by a highly trained security expert whose ethical behavior is unquestionable. Additional defenses such as intrusion detection, intrusion prevention, and things that we haven't discovered yet are also in operation. Think of the first computer as residing at ground zero, and the second one at infinity. Envisioning several continuums that start at zero and extend to infinity might represent a better understanding. Each one could represent one of these parameters, such as user ethics, knowledge, or secure design. The position of the computer on the composite continuum can then be expressed as a combination of its location on all of the separate continuums. This representation is not static. Think of each point on the continuum as a marker, like the wooden rings on an old abacusthey are meant to be moved.

If you accept this representation, then you can see the definition of your job in securing the computers on your network. Your job is to push these markers as much as you can to the right toward infinity. Which markers you individually push will depend on your current job and abilities, but push you must. Some of the markers can't be pushed at all; you can't change the design of a current operating system (although you may be able to push its manufacturers to make some attempt at dealing with a poor design), and you probably can't change the behavior of people whose purpose in life is to destroy things in the name of figuring out how they work or who simply want the financial reward inherent in doing so.

This book will help you move the markers on one of these continuumsthe hardening onefor Windows Server 2003. When you do that, you will also move the marker on the composite continuum, but I don't think you'll be fooled into thinking that your work is the only thing necessary to secure your computing infrastructure. This book will also advise you of things you can do to push the markers a little bit more in some of the other areas, but in the end, the security composite of your network will depend on more than can be represented in this book.

Start here by learning or reviewing basic security principles, and then use the rest of this book to help you understand how to use these principles to secure Windows Server 2003.