Unauthorised Access: Physical Penetration Testing For IT Security Teams

7.2. Introduction to Wireless Cryptography

There are a number of ways that wireless access points can be secured (or at least made more secure). The most common, and indeed baseline, approach is the use of encryption. Encryption ensures that traffic is only readable by those who have the key and, in the most commonly deployed wireless networks, the key is the same thing as the password that a user uses to join the network. The two main variants of wireless encryption are WEP and WPA and we discuss them briefly before showing ways of attacking them.

Figure 7.1. A typical wireless network.

7.2.1. WEP Shared Key Encryption

Despite the fact that Wired Equivalent Privacy (not Wireless Encryption Protocol, as many seem to think) is known to have severe flaws that lead to it being cracked quickly and easily, WEP is still widely deployed in homes and businesses as the sole security mechanism. I guess people don't believe that anyone's going to take the time and trouble to break in or they think that the cryptographic attacks in question are so technically advanced that they don't worry about it too much. Neither of these beliefs is accurate.

Although WEP was first identified as having serious flaws in 2001, it is still presented as the first security option during configuration. Manufacturers continue to support WEP as some older systems don't support the newer, more secure wireless ...