Hot on the heels of "war driving" (see Information Age, June 2001) comes "war chalking", the digital equivalent of the bush telegraph for hackers looking for unprotected wireless Internet access.
Wireless networks are almost too easy to access – and therefore extremely vulnerable to abuse. For users, the process of logging on to a wireless network is almost 'zero configuration': Just walk into a room with an appropriately equipped laptop, and you can automatically join a network, access peripherals and surf the web without having to change a single system setting.
Unfortunately, this level of ease-of-use means that security on wireless networks is typically poor, and since there are no wires involved, hackers do not need physical connections to the network for their computers to tap into it and access systems residing behind the firewall.
War chalking is a code developed to advertise the presence of wireless networks. Scrawled in chalk on pavements, walls or other objects, a so-called 'war chalk' uses a set of symbols to alert wireless users to the location, speed, network name, security and type of a network nearby. Our hypothetical example shows the war chalking symbols for an open network called 'infoconomy', that uses the 802.11b protocol running and offering 11Mbps bandwidth, located at a distance of 25m to the right of the symbols, and provides a web site address for more information about who is running the network.
Hackers are not the only ones responsible for war chalk. Many people have deliberately configured their wireless networks to be open so that they can share their broadband Internet access with anyone who needs it. One of the inventors of war chalk, web designer Matt Jones, says that war chalk is "being recognised for the public good" it provides. And while it has become an almost universal language for hackers, there are already problems with translation: French hackers have created their own language and are refusing to adopt the English symbols. But if a company has a wireless network and IT staff have suddenly noticed strange signs outside on the pavement, it might be time to tighten security…