Changing just one line of code in the Linux OS could, potentially, allow hackers to monopolise the bandwidth available at 802.11 hotspots.
By altering the Multiple Access Control (MAC) protocol, one of the series of protocols that govern how bandwidth is distributed between multiple users of the same wi-fi access point by randomly assigning each hotspot user a rate for data transfer, it is possible to siphon off most or all of the bandwidth.
The discovery inspired Imad Aad and his colleagues, of the Federal Institute of Technology in Lausanne, to devise a counter-measure.
Aad said wi-fi operators using a tool called Domino could detect in a third of a second if someone is doing this by monitoring the rate of data flow in the MAC layer.
The tool can be set to raise an alarm when one user is receiving data at an abnormally high speed compared with other users.
"The new generation of wireless adapters allow easy modification of previously inaccessible MAC protocol parameters," said Aad.
"With a single line of code hackers can reduce the contention window size, realising a considerable redistribution of throughput shares among stations competing for wireless bandwidth."
Aad and his EPFL colleagues hoped to patent the device.
Written by staff at LinuxWorld