To be effective, access control must be based on a value that is not easily spoofed. Unfortunately, MAC addresses are easy to sniff because they are transmitted in plaintext. All an attacker needs to masquerade, as a legitimate station is a wireless NIC operating in promiscuous mode for capture, with a configurable address to enable spoofing. Some stations can be programmed with an SSID they must present in order to associate with an access point. Unfortunately, because SSID is broadcast in plaintext in many 802.11b frames, it also easy to sniff and spoof.
Effectiveness depends upon the authentication method used and whether it requires confidentiality.
Corp. All Rights Reserved.