The security of wireless networks used by businesses in London has improved significantly over the last 12 months, says a survey.
Wireless networks are popular in the City
RSA Security found that 66% of the networks surveyed use the encryption system built-in to the wi-fi standard to help them prevent unauthorised access.
This is a big change since the last survey which found that only 37% had the security system turned on.
Despite this improvement, RSA said many firms were still making basic mistakes on wireless security and were leaving themselves open to attack.
Free to air
Wireless networks have proved hugely popular with many businesses because they are so easy to set up and they eliminate the need for expensive cabling to give workers net access.
But this ease of use comes with a price.
The radio signals transmitted by wireless networks often leak beyond a building's walls leading many hackers, both hobby and criminal, to carry out so-called wardriving expeditions to map wi-fi hotspots.
The RSA survey found that the popularity of wireless networks has not been dimmed by the publicity about the technology's security failings.
A Pringles tube can help locate a wi-fi network
If found that the numbers of wireless networks being used by London businesses has risen by 235% in the year since the last survey.
Many are more secure than last year too and have the basic Wired Equivalent Privacy (WEP) system turned on. This scrambles signals to make it harder to use a wi-fi network without permission.
It found that many other networks are protected with other techniques that stop people outside a business using the net or getting access to internal networks.
But despite the good news, RSA said that many firms were still not doing the basics to ensure that they were protected.
About a quarter of the networks surveyed, almost 300 wi-fi access points, were poorly protected.
Research author Phil Cracknell said that many firms used the default settings for wi-fi hardware they were installing making it easy for malicious hackers or criminals to eavesdrop or steal net access.
He said many departments could be buying their own networks and posing big problems for corporate security.
"The price of access points has fallen rapidly and can now be bought for as little as £140 - a purchase that could easily be made on expenses," he said.