CertiGuide to Security+  9  Chapter 2:  Communication Security (Domain 2.0; 20%)       9  2.6  Wireless

2.6.1  WTLS 1 2 2.6.3  WEP/WAP

What Info Do You Need to Join an 802.11 LAN?

The way 802.11b works is that if you possess a couple pieces of information, which are shared among network users, you can access the network. There is generally no individual authentication when gaining access to the network. The two pieces of information required to communicate over an 802.11b LAN are the SSID and, if encryption is enabled, the WEP key.

The SSID²⁴⁰ (Service Set Identifier) is a 32-character identifier that is attached to each packet, identifying the wireless LAN to which the traffic belongs, so that multiple wireless LANs can exist in the same physical area. Much like multiple Windows workgroups can exist on a single physical LAN, and an individual can select the workgroup to join by setting its name in their system configuration, a user can select the 802.11b LAN to participate in by setting the proper SSID. All users who desire to communicate with each other typically set their SSID to the same value. Since the SSID can be “sniffed” from the network via programs that monitor wireless LAN activity, and once known, anyone can set their wireless network adapter’s SSID to the desired value, the SSID really is only a LAN selection feature for user convenience, not an access control feature designed to add security.

The second piece of information is the WEP (Wired Equivalent Privacy) key, discussed in the next section.

2.6.1  WTLS 1 2 2.6.3  WEP/WAP