This one's on the house

PUBLISHED : Sunday, 17 November, 2002, 12:00am
UPDATED : Sunday, 17 November, 2002, 12:00am

BY NOW, you probably know all there is to know about spam. But it's not the spam itself I want to talk about. An inbox full of garbage is only half the problem; there is also an attendant loss of privacy. Just how much do those people oh-so concerned about your dental cover, home insurance and desperate need for old TV programmes know about you?

To reiterate the golden rules of dodging spam: don't post your e-mail address on the internet; and never open or reply to a spam message, especially to ask to be removed from a mailing list. Simply delete the messages. You can complain to your internet service provider (ISP) or, better yet, the spammers', and hope at least one of them takes action. But spammers have found a new way that makes them almost impossible to trace or block, and which may amount to more of a threat to your privacy than anything that has gone before.

Wireless LAN (Local Area Network), Wi-Fi and 802.11b are all names for the same system; buy a hub, make your broadband internet connection and you can gain access to the net wirelessly from anywhere in your home using a small PCMCIA card plugged into your notebook. You can create a network with desktop computers, and give them all access to the internet without having to string kilometres of wire round your furniture. And here's the catch: while these wireless systems provide password protection, not everyone turns it on.

All a spammer-cum-hacker needs to do is park his car outside your home or office, open his notebook computer and connect to the internet via your hub. How does he know you're online? Wireless hubs, which have a range of about 50 metres, send out radio signals, which the spammer can easily detect via the wireless card in his computer. He'll be in and out in a few seconds and no one will ever know he was there. By the time the ISP takes action he'll be long gone, having sent thousands of e-mails from your address. Worse, the ISP may take action against you for spamming and cancel your account.

Sound like fantasy? Sound like the sort of thing that happens to other people in other places? I recently bought a PCMCIA card, inserted it into my hand-held computer and tried an experiment in my living room. To my surprise, it connected to the internet and began downloading a web page. I was surprised because I don't have a wireless hub or a broadband connection, only the card. One of my neighbours, however, has a Wi-Fi set-up and had failed to use any password protection. Walking through my neighbourhood, I was able to connect to the net outside many low-rise buildings.

This not only gives anyone with a wire-less card unencumbered access to your internet service, but potentially to your computer. In some cities, particularly London, where local phone calls are expensive, finding unprotected machines has become such a fad that hackers are leaving chalk marks on pavements outside buildings to let others know where they can find unobstructed net access.

If you have a wireless hub, use security measures. Some of the more expensive hubs allow encryption, giving a second layer of protection, but even that is not impenetrable. Turn off your computer's file-sharing function, or turn off the computer and hub when you're not using them. Even with password protection turned on, a novice hacker can bypass that defence and need be within only 50 metres of your hub to do it. In Hong Kong, there may be lots of people within 50 metres of your hub.

The 802.11i communications standard, due out early next year, will usher in much tighter security. Meanwhile, Cisco, Nortel and several other companies offer proprietary security schemes with better protection than standard Wi-Fi set-ups. If you already have a Wi-Fi hub, don't despair. As long as it is flash ROM upgradeable, you should be able to convert it to 802.11i when it becomes available.