This book is organized into three parts. Roughly speaking, these parts describe:

  • Things you should know about security in general

  • How both the old and new methods of security work in Wi-Fi networks

  • Real-world issues and examples of attack tools that have been (and continue to be) used

In Part I, "What Everyone Should Know," we review issues that everybody should know about security. Some of these issues are commonsense, but you may not have thought about them. If you are already a security expert and exploring how security works for Wi-Fi, consider skimming this material because many of the principles will be familiar.

Part II, "The Design of Wi-Fi Security," starts with a primer on IEEE 802.11 that runs through the basics of Wi-Fi systems communication. It describes the types of messages that are exchanged, usually hidden from the end user, and explains how a portable device like a laptop can find, select, and connect to an access point. The primer contains a moderate, but hopefully not oppressive, amount of detail. You need to understand the messages being sent between the Wi-Fi components to appreciate the security risks.

After the primer, the book delves into the security protocols for Wi-Fi. It describes the original Wi-Fi security approach, WEP, and explains why this method is no longer considered secure. It then covers the new approaches of Wi-Fi Protected Access (WPA) and IEEE 802.11i Robust Security Networks. Both the new methods share a common approach and are scalable from small networks of a few devices up to international corporations. The solution involves many pieces assembled in layers. This makes the approach appear complicated but, if you take one layer at a time, you can understand each part separately.

Part III, "Wi-Fi Security in the Real World," returns to practical issues. We start off with a review of security in hotspots or public access networks. Such network access is becoming increasingly popular in Internet cafes and airports; and hotspots bring their own special security risks. We then look at some of the tools available on the Web that anyone can download for attacking wireless LANs. Our philosophy here is that it is only by sitting in the cockpit of the enemy's plane that you can understand the threat it poses. Finally we make recommendations about practical actions for designing a secure network and look at an open source project that has been established to set up and test the security approaches that you will need to deploy.

We have not focused on specific vendor products. In the end each vendor will package the new security approaches in its own way. They will hide the complexity behind graphical user interfaces and try to simplify the installation and maintenance as much as possible. All this can make life easy for you if you are deploying the equipment. However, while the work required to install systems can be boiled down, we believe that the understanding of what is going on should be sharpened up. Why? Because at the end of the day, you're the one that gets hurt by attacks, not the vendor.

There is no "neighborhood watch" scheme for network security. The administrator or owner of the equipment must be aware of the risks and be proactive in response. Of course most people can't afford, and don't want, to spend all their time working on security issues. We all welcome shortcuts from vendors that simplify or set up the systems. However, remember that salespeople are optimists, but security people must be pessimists.

Our advice to you is simple: Be informed. Take advantage of vendor tools to simplify installation and management but understand what they are doing. Know enough to decide what is best for you and to tweak under the hood when you think it is necessary. Make better purchasing decisions and sleep well at night. Helping you meet these goals is the purpose of this book.

    Part II: The Design of Wi-Fi Security