No wires, no worries?

Wireless networks sound great. The sprawling mass of cables currently linking your office computers together can be thrown out and replaced with a single transmitter which won't get in anyone's way.

All correctly equipped electronic devices, from fridges to laptops, can be linked to the system - it's cheap, easy and the results are immediate. Little wonder wireless networks have been popping up all over the UK. London has seen an explosion: a year ago these systems numbered in their hundreds, now there are more than 5,000.

But before people get too excited and jump on to the bandwagon, be careful - not everything is rosy in wireless world. According to a recent report, almost all the London networks are highly vulnerable to attack.

An International Chamber Of Commerce-sponsored survey found a staggering 94 per cent of the capital's wireless systems have not taken even the most basic steps to protect themselves against hackers.

The networks may have only a limited range but they are not difficult to find and a software tool freely available on the Net makes it easy for anyone with the right tools to spot access points - it is even possible to pinpoint them with an antenna made out of a can of Pringles crisps.

Once these points have been found, it is simple to read confidential information sent around within the system. Hackers driving around in cars, doing what has become known as 'drive-by hacking', can intercept anything from e-mails to financial transactions. And those not interested in stealing data can use the wireless network to piggyback on a company's fast Net connection, essentially getting their Internet access for free.

Neil Hare-Brown, of information security company QCC, believes the companies selling wireless systems have a lot to answer for. He said: 'The suppliers want to make it easy, so that everything can be done out of a box. But they are not supplying the software in a secure mode - it's like car companies selling cars with no locks on them. They should have a simple wizard program on the software which takes the user through the process of securing the network.'

The simple security steps include using passwords and implementing an encryption system, but even when these are set up, wireless networks will still be open to sophisticated hackers. Mr Hare-Brown says: 'Internal networks are open as well, but they benefit from the physical security that surrounds them. Wireless networks don't do that and their encryption systems are not that difficult to crack.'

As with most new computer technology, it seems the attitude is to get people using it and worry about security later. But people must not assume suppliers have made their systems safe and should take their own steps to ensure they are protected.