Chapter 4 provides an overview of the different types of attack that a Wi-Fi LAN must defend against. Some types of attack are quite obvious, but many are subtle and done in unexpected ways. These subtle attacks are the most dangerous because they exploit our assumptions about where the vulnerabilities lie. We focus on attack concepts. Later, in Chapter 15, we provide a much more detailed and technical analysis for certain known attacks that have been successful against early Wi-Fi systems.
As we build our defenses, it is important to understand the types of attack we may encounter. The technical approach of an attack can vary from crude to sophisticated, but the fact that an attack is crude doesn't make it ineffective. For example, if someone steals your laptop while it is logged onto the network, they have made a successful, albeit crude and detectable, security attack. More sophisticated methods of attack, however, allow an attacker to gain access without being detected and these methods are more dangerous. Detecting a security breach is a close second in importance to preventing the breach. For example, if a security breach were detected immediately and appropriate responses taken, service might be disrupted but the damage might be considerably reduced. By contrast, if an intruder were allowed to break in multiple times over an extended period, the consequences could be catastrophic. The smarter the attacker is, the more careful they will be to avoid detection.