Wireless client devices that are conﬁgured correctly minimize network performance issues that the user may experience.
Common Wireless Client Conﬁguration Issue and Description
Protocol compatibility: Compatibility issues exist between the different versions of the 802.11 wireless protocol implementations. For example, 802.11b is not interoperable with 802.11a.
WEP weaknesses: The Wired Equivalent Privacy (WEP) protocol standard is deprecated as a very weak security standard. The problem stems from the way WEP produces the keys that are used to encrypt data. Because of a ﬂaw in the method, attackers can easily generate their own keys by using a wireless network capture tool, to capture and analyze data transferred through the air. Wi-Fi Protected Access (WPA) is a security protocol introduced to address some of the shortcomings in the WEP protocol.
Buffer overﬂow: A buffer overﬂow occurs when too much data is fed into a ﬁxed length memory buffer, resulting in adjacent areas of memory being overwritten. If done intentionally by an attacker, a buffer overﬂow can open the target system up to a number of further attacks. As with desktop and server applications, it is also possible for applications on wireless devices to be vulnerable to buffer over- ﬂows, which may cause the device operating system to crash or reboot, and may also cause the loss of data or execution of rogue code on devices.
Viruses: There are viruses and Trojans that affect wireless devices speciﬁcally. In fact, Symantec distributes a version of its antivirus software for Palm®OS. Like other viruses, those that affect wireless devices cause trouble, typically by deleting or corrupting data.
Data stored in plain text: Often, users store personal and conﬁdential information (for example, social security numbers, medical information, and credit card numbers) on their handheld devices using a built-in text editing application or the device’s contact manager. These contact managers do not always store their information in an encrypted format. Palm OS permits the user to specify records as Private, but this is not an encrypted format and is easily accessible by an attacker familiar with the inner workings of the operating system, which means much of this data is accessible to crackers who have either stolen or temporarily borrowed a device.
Lack of authentication: By default, many wireless access points (WAPs) will accept communications from just about any wireless device. While this might seem ideal because it means easy access to network resources without a lot of conﬁguration, it also creates the perfect opportunity for the wrong people to get into your network.
Unused connections: Unused wireless connections make your network vulnerable to security breaches because an attacker may go undetected for a greater length of time. The attacker could crack various security mechanisms such as authentication keys. Or, the attacker could take over a valid user’s session on the wireless network, known as hijacking.