The magazine of the Melbourne PC User Group Wireless Security Keeping Your Information Where It Belongs...In the Air Jim Hanks

Already thriving within the telecommunications market, wireless technology is preparing to embrace computing on an even larger scale. Presently, most people encounter wireless local area networks (WLANs) in airport lounges and tech-savvy offices. But in a few years, most offices will have their own networks. Soon, the general population will be able to use their laptops and wireless service providers to surf the Internet from anywhere they like. And eventually - straight out of sci-fi culture - retinal scanning displays will allow an angry glare at your coffee pot to initiate your morning brew.

As wireless networks become more pervasive, some people are getting scared. When most of your decisions are carried out via frequencies, will your toys eventually stop listening to you and start talking to strangers? Unfortunately, riding alongside that superhero called Wireless Communication is his malevolent sidekick, Easy Access.
 
Access is one of the inherent dangers in progress. When new technologies are quickly constructed, sometimes there's not enough time to make sure the back doors are all locked. Recently, in San Francisco, a security expert attached a wireless data antenna to his car and was able to enter the WLANs of almost 80 companies using his laptop - during a one-hour ride. Forget about drive-by shootings, that car slowly rolling down the street with its lights off (and the monitor glare inside) is probably gunning for online-banking passwords. And yours may be next.

Don't lose too much sleep, though, severe paranoia is not warranted. There is plenty being done to keep information safe; in fact, the real problem might be your own negligence.

The History of Wireless Security

Understanding the complexities of wireless security is easier when you consider the history of communications. Basically, mobile phones, handheld devices, and WLANs are radio transmitters and receivers; and all of these devices are the technological descendents of cordless telephones. Cordless phones experienced many of the same problems as WLANs do now. Drive-by hacking isn't a new concept, but twenty years ago the hackers only wanted to eavesdrop or access your phone line to make free calls. So, how were these security breaches blocked?

One of the first methods of security developed for wireless communication was channel hopping. First invented during World War II, channel hopping prevented the jamming of torpedo signals. Forty years later, a variation of channel hopping was implemented to secure cordless communications. By moving (or hopping) a transmission to different random channels while the receiver moved in kind, eavesdroppers (and nosy neighbors) were thwarted. Of course, craftier individuals soon figured out how to anticipate the hopping sequences.

Digital technology posed the next barrier to the nefarious. Previously, intercepting analog signals could be accomplished by tuning a radio scanner to the appropriate transmission frequency. However, once digital technology translated voice signals into binary code before transmission, privacy invasion became a more complicated affair. But this too was soon cracked. The next layer of security was provided by digital security codes. This early form of authentication made a hacker's work more difficult by establishing a random code every time a handset was placed in its base station. This code was then transmitted continually throughout a call and in order for a handset and its base station to communicate, both needed the code. Digital security codes are still used in cordless phones today, along with a newer defence: Spread Spectrum Technology (SST). This system disassembles a digital signal and then spreads it across several channels during transmission. The receiver then reassembles the signal before translating it back into voice.
 
All of these security measures are employed in some form or another by today's cellular phones, and all are fairly effective. But now that data networks are going wireless, hackers have shifted their attention. When you can download everything from an office's network (including e-mail), why waste your time listening to telephone conversations?

Wireless Local Area Networks (WLANs)

Whether a network is sending data signals or voice signals, security issues aren't as different as you might expect; both signals are transmitted digitally, so defense tactics are similar. But before we get into security measures, let's discuss the WLAN technologies that are available.
 
Presently, most wireless networks are based upon the Institute of Electrical and Electronic Engineers (IEEE) specification 802.11. There are two systems that follow this standard: SWAP (Shared Wireless Access Protocol), which uses a form of channel-hopping technology; and Wi-Fi (Wireless Fidelity), which uses a form of Spread Spectrum Technology. Each method has some advantages and disadvantages, but, generally speaking, Wi-Fi is faster (up to 11 Mbit/s), has longer range (about 170 metres), and is more expensive (approximately US$500 per unit). Meanwhile, SWAP gives you about 1 Mbit/s of speed, works from 35 metres away, and costs US$100 per unit. Given these respective characteristics, Wi-Fi is generally marketed toward offices and SWAP is marketed toward homes. Macs (and many PCs) have embraced Wi-Fi - and with Apple's Airport access points (US$299) and Airport PC cards (US$99), setup is surprisingly inexpensive and simple.

A third technology, Bluetooth, is the much-awaited standard that is expected to integrate most electronic devices. Using a different specification (IEEE 802.15.1), these devices will unconsciously locate each other with channel-hopping technology and a data speed comparable to SWAP (1 Mbit/s). Most importantly, due to its inexpensiveness, Bluetooth can be installed in everything from mice to microwaves. Originally, Bluetooth was expected to swiftly hit the market this year but recently discovered design flaws have delayed mass deployment (and led to Microsoft's decision not to support Bluetooth in the next version of Windows). As for Bluetooth's security, it has yet to be fully assessed; but if there's a wireless way to get into your kitchen, bored teenagers will definitely find it.

Although security is inherent in each of these transmission technologies, all are vulnerable to attack. More experienced hackers are not phased by channel hopping, digital security codes, and spread spectrum technologies. Keeping signals safe requires some extra steps.

During the aforementioned security breaches in San Francisco, most exploited systems (which used the 802.11 standard) were vulnerable because the security provided was not properly used (and was sometimes not even enabled). WLANs with 802.11 technology use a wireless encryption standard called Wired Equivalent Privacy (WEP). Although WEP has weaknesses, most security breaches can be avoided if WEP is correctly employed. Default settings for encryption keys should not be used, as they are well known to hackers. Also, users should not use their network names for passwords since they can be easily guessed.
 
Additional security problems stem from WLAN users' misbelief that WEP provides end-to-end security. Unfortunately, it does not. IEEE designed the WEP with the assumption that, by restricting physical access to a building, a company could prevent unauthorized wireless access. The designers did not anticipate the ease with which signals could travel through building walls. IEEE has assured the public that it is strengthening the security of 802.11 by improving the authentication process; the new version should be available within a few months. Meanwhile, encrypting your sensitive files and installing a firewall is advisable. If you already have a firewall, make sure to locate your access points outside of the firewall; otherwise, you are opening up your entire network to wireless attacks. Another good suggestion is to turn off file and printer sharing capabilities if you don't use them. Files are safest when they are isolated.

Since WLAN security holes provide the same access for hackers that the Internet has provided for years, you might want to review April PC Update http://www.melbpc.org.au/pcupdate/2104/index.htm for in-depth explanations about the latest ways to protect your files. Additionally, a recent article by PC World http://www.pcworld.com/features/article/0,aid,44543,00.asp reviews the various firewall, encryption, and antivirus tools. 

Despite the various dykes that have been constructed to stop the unauthorized flow of information, leaks will sprout and the thumbs of security will twiddle before they figure out how to plug the holes. In review, here are a few things that you can do to avoid WLAN security breaches:

• Don't use default encryption keys
• Use obscure passwords and change them often
• Install a firewall and put your WLAN access points outside of it
• Deactivate file and printer sharing capabilities if you don't use them
• Encrypt your sensitive files (and e-mail)

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