New hacking threat to firms
Business leaders are warning a new craze called "war chalking" can leave firms open to hackers.
It involves drawing symbols in chalk on walls and pavements to mark points where signals from nearby office networks can be tapped into.
Anyone with a suitably-equipped laptop can then switch on and surf the web.
The Confederation of British Industry says it incites illegal acts and exposes sensitive data to cyber criminals but others claim it is harmless.
It has occurred on the back of an increase in the number of office PC networks connected with wireless signals instead of cables.
It began as a scheme designed to let people share Internet access which already exists. But there are fears businesses whose wireless network leaks beyond the office walls and into the street could become targets for hackers.
A spokeswoman for the CBI said: "The CBI condemns war chalking as an implicit incitement to irresponsible and illegal acts."
"Hacking company networks could potentially provide access to commercially sensitive data, and is a security risk," she went on.
"War chalking could harm businesses financially and operationally, while also compromising the confidentiality of customer information," she added.
But Ben Hammersley, a freelance writer who says he launched the craze, with the first chalk mark outside his house in London five weeks ago, said: "The potential use of war chalking for hacking purposes has been highly overblown."
He went on: "A hacker who found that a system was insecure would be extremely unlikely to find anything useful to him or her," adding: "If people want to do harm, they are hardly likely to mark the place where they have been with chalk," he added.
