Wireless networks and security issues.

Abstract

The evolution of different wireless standards (known as 802.11 standards) in the late 1990s produced an astonishing volume of global demand for wireless networks. Many organizations and residential computer users have embraced the convenience and mobility of the wireless networks. In this article, the various wireless standards currently in use will be examined. Furthermore, different characteristics of these standards will be investigated. Finally, the security issues of wireless networks affecting corporations and residential setups will be addressed.

Introduction

Recent developments in wireless technology have created an enormous opportunity for consumers and corporations alike. Consumers in general have moved away from wired networks and embraced the new technology. Wired networking--which is based on sharing data, hardware and software among connected computers by using cable or wire--is also known as Local Area Networks (LANs). On the other hand, in wireless networks, computers are connected by transmitting radio waves or, less commonly, infrared light. Generally, wireless networks can be constructed in two ways: 1) by using a peer-to-peer setup or 2) by using an access point.

In the peer-to-peer setup, several computers--each equipped with a wireless network interface card--can communicate directly with other wireless enabled computers. Although each connected computer can use file sharing and printing resources, it may not be able to access wired LAN resources, unless one of the computers with special networking software (Software Access Points) is used as a bridge to the wired LAN. In the second type of setup, a wireless network uses an access point or a router. Here the access point acts like a hub, providing connectivity for the wireless computers, which are equipped with network interface cards. It also can connect a wireless LAN to a wired LAN and create what is known as a Hybrid Network, allowing wireless computer access to the wired LAN resources, such as existing Internet connectivity or print and file sharing. Since the price of a router or access point has declined substantially during the last few years, these days the typical home or office wireless network is based on the router. In the wireless LAN (WLAN) several mobile computers are connected to the access point or router. The access point has two functions: 1) to control the operation of a wireless station (through transmission power, for instance) and 2) to link mobile users to wired LANs [4].

Using a home or office wireless network, one can connect several computers to share hardware, software and resources--such as stored files, photos, printers and an Internet connection. Furthermore, from each computer, one can print stored files, photos or documents by sharing a single printer attached to just one computer (i.e., a printer server)--all without using cables running throughout the physical space. By using a wireless network a home or office can have the ability to share a single high-speed broadband cable or DSL connection among several computers without significant reduction in the connection throughput (speed). Indeed, wireless networks can be expanded easily to serve a dozen users or more. However, one must make certain that the equipment included within a wireless network is Wi-Fi (Wireless Fidelity) certified. In order to check if a particular device is Wi-Fi certified, one can visit the Wi-Fi Alliance web site [2]. Also, through this web site, one can make sure that various equipment one purchases is compatible with equipment already installed in a system.

In workplaces and offices, the built-in flexibility of wireless networks has created a valuable connectivity between the mobile salespeople and behind-the-scenes workforces. In today's dynamic business environment, a wireless network provides a superb and affordable means of instant communication. Important characteristics of various wireless standards are summarized in Exhibit 1.

Security

Security has been one of the major problems with wireless networks. By default, a wireless network is designed to provide easy access. Generally, wireless networks need to announce their existence so that potential users can link up and use the services provided by the network. However, radio signals traveling through the open atmosphere can be intercepted by individuals in the vicinity who have access to wireless devices with the right software for interception. As a result, if not properly configured, the signals can be located and monitored quite readily.

Another security problem of the wireless network involves rogue access points. Any local computer user can purchase an access point, and potentially connect it to the corporate network or a home network in the vicinity without authorization. Rogue access points deployed by end users pose great security risks.

In addition, traffic analysis and eavesdropping present a third common problem. Not all the wireless standards available in the market provide protection against attacks that passively observe traffic. The main risk is that these standards do not provide a way to secure data in transit against eavesdropping. A computer user equipped with a wireless network analyzer could easily capture unprotected Internet protocol radio transmission. A very generic solution available is a Wired Equivalent Privacy (WEP) system. However, it will protect only the initial contact with the network. When WEP is employed, data is not encrypted or authenticated, leaving an attacker with the opportunity to disrupt transmissions.

Generally, home computer users are not security experts and may not be aware of the risks posed by wireless networks. Furthermore, wireless security is a work-in-progress, with evolving standards. However, home wireless network users can take several steps to reduce the security risk posed by the wireless transmission of data and sensitive information by changing their router default setups [3]. The following steps can be taken by using the router manual.

1. Change the default password of the router. Routers use a preset password initially, and it's easy for an unauthorized user to figure out.

2. Disable remote router access. This will keep anyone from accessing your router from a remote location through the Internet. However, it does not prevent local wireless users from accessing your wireless networks.

3. Change the Service Set Identifier (SSID) in order to disable broadcasting. SSID is the ID of your own local wireless network and it reveals the network to anyone in the vicinity who is using a wireless-equipped computer. All wireless routers come with a default SSID that you should change. You'll need to remember it in order to set up other wireless clients on your network.

4. Turn on your router firewall. Routers usually have their firewall turned on by default, but make sure that's the case. Also, enable any additional firewall features, such as the ability to block anonymous Internet requests. To increase your security, run a software firewall on every PC on your network.

5. Enable data encryption. Data transmitted by a wireless network can be read by anyone who picks it up, unless it's encrypted. Wireless routers have encryption capabilities. Wi-Fi Protected Access (WPA) is the standard that offers the most protection for data. Some routers are equipped with 'WPA Pre-Shared Key' (WPAPSK). This value will provide higher security for home or small-business networks.

6. Enable MAC filtering. The Media Access Control (MAC) address is a unique identifying number assigned to each network device. Enabling MAC filtering in your router improves your network's security by accepting transmissions only from PCs with specific MAC addresses. You can also prevent certain MAC addresses from accessing the network.

When sensitive information is transmitted over the Internet, a few more precautionary steps must be taken in addition to the above-mentioned measures. Wireless network users, just like other Internet users, must make sure that they are using a secure connection. Using Internet browser windows, there are two ways to recognize if the web site one is accessing is secure:

1. You should see that the "http" in the address line is replaced with "https" and

2. You should see a small padlock (resembling a small lock) in the status bar at the bottom of the browser window.

Conclusion

Wireless technology has been evolving rapidly during the past few years. Faster devices and more secure equipment are being introduced into the market every day. "Once the stuff of science fiction, wireless networks have rapidly become an integral part of most organizations' network structure. In fact, for small offices and many homes, wireless networks have evolved to be the only network structure" [1]. Recent developments in wireless networking have made the mobility and convenience of the wireless network even more appealing to the average computer user.

References

1. Goldman, J. and P. Rawles. Applied Data Communications: A Business-Oriented Approach, 4th edition. Danvers, MA: Johns Wiley & Sons, Inc., 2004.

2. http://www.wifi.org/OpenSection/certified_products.asp? TID=2 (accessed May 1, 2005).

3. Miastkowski, S. "How to Build a Safe, Secure Network," PC World, May 2004. www.pcworld.com/news/article/0,aid,115066,pg4,00.asp

4. Panko, R. Business Data Networks and Telecommunications, 5th edition. Upper Saddle River, NY: Prentice Hall, 2005, p. 218.

Farok Vakil, The Peter J. Tobin College of Business, St. John's University

EXHIBIT 1. WIRELESS STANDARDS

                    Data Throughput      Data Throughput
Standard            (Theoretical Speed)  (Practical Speed)

802.11              Up to 2 Mbps         1 Mbps
802.11b             11 Mbps              6 Mbps
802.11g**           54 Mbps              27 Mbps
                                         (g-only networks)
                                         9-13
                                         (b/g combination networks)
802.11a             54 Mbps              27 Mbps
802.11 super a + g  108 Mbps             54 Mbps
802.11h             54 Mbps              27 Mbps

Standard            Frequency Band       High Interference

802.11              2.4-2.4835 Ghz       Yes*
802.11b             2.4-2.4835 Ghz       Yes
802.11g**           2.4-2.4835 Ghz       Yes
802.11a             5.12-5.25 Ghz        No
                    5.47-5.725 Ghz
                    5.725-5.825 Ghz
802.11 super a + g  2.4 GHz 802.11 b/g   No
                    or dual band 2.4/ 5
                    GHz 802.11 a/b/g
802.11h             Same as 802.11a      No

*Since 2.4 GHz has only three non-overlapping channels, users may share
this frequency with their neighbors' wireless networks or other wireless
devices, such as cordless phones and microwave ovens. These wireless
devices are competing for space on the 2.4 GHz frequency. Consequently,
a high interference rate might be observed. On the other hand, 5Ghz
wireless has 16 non-overlapping channels (802.11 super a + g) and 24
non-overlapping channels (802.11a and 802.11 h), so the possibility of
interference is very low.
** (802.11g) devices work with (802.11 b) devices albeit at lower speed.