Managing Cisco Network Security, Second Edition
A completely updated sourcebook on Cisco Security Management.
TABLE OF CONTENTS Managing Cisco Network Security, Second Edition
Spoofing and Unauthorized Access
The combination of weaknesses in WEP, and the nature of wireless transmission, has highlighted the art of spoofing as a real threat to wireless network security. Some well publicized weaknesses in user authentication using WEP have made authentication spoofing just one of an equally well tested number of exploits by attackers.
Defining Spoofing
One definition of spoofing is where an attacker is able to trick your network equipment into thinking that the connection they are coming from is one of the valid and allowed machines from its network. Attackers can accomplish this several ways, the easiest of which is to simply redefine the MAC address of your wireless or network card to be a valid MAC address. This can be accomplished in Windows through a simple Registry edit. Several wireless providers also have an option to define the MAC address for each wireless connection from within the client manager application that is provided with the interface.
There are several reasons that an attacker would spoof your network. If you have closed out your network to only valid interfaces through MAC or IP address filtering, if an attacker is able to determine a valid MAC or IP address, he could then reprogram his interface with that information, allowing him to connect to your network impersonating a valid machine.
IEEE 802.11 networks introduce a new form of spoofing: authentication spoofing. As described in their paper "Intercepting Mobile Communications: The Insecurities of 802.11," the authors identified a way...
Copyright Syngress Publishing, Inc. 2002 under license agreement with Books24x7
