Internet hubs are vulnerable to attack

A new study of the structure of the internet indicates that, because of the net's reliance on a few key connections, a sustained attack by terrorists or hackers could bring it down.

Most of the traffic on the internet jumps from connection to connection as it makes its way to its destination. If one or more of the connections fail, the traffic simply finds another route and completes its journey.

However, the study reports that while most routers have only a few connections, a number are major hubs. Should a sufficient number of the major hubs fail, the system could be divided into separate areas that are no longer connected with each other.

"If you go for the biggest nodes and take a couple of them out, you can break the system into clusters that don't communicate with each other," said Albert-Laszlo Barabasi, a physicist at the University of Notre Dame and co-author of the study.

While the possibility of bringing the internet to a halt does exist, that scenario is unlikely, according to Jim Jones, director of technical operations at Global Integrity.

The study reported that the average performance of the internet would be reduced by a factor of two if one per cent of the most connected nodes are disabled, and it would take four per cent being disabled to make the network fragmented and unusable.

"The attack would have to hit all those sites at the same time," said Jones.

There are two ways to attack crucial nodes - physically or through the network, he added.

Blowing up the sites would be difficult because they spread throughout the world, and are highly secure with redundant power supplies and fire suppression systems. "A physical attack would have to be a well co-ordinated, fairly well-funded attack on multiple sites," said Jones.

Using the network method of flooding the sites would also be difficult because the attack would have to be sustained against multiple sites for a long period of time. "The longer the attack is sustained, the more likely a trace back is," he added.

Jones said it is difficult to determine the real susceptibility because actual live tests have not been done and won't be. "Nobody's willing to bring the sites down to see how strong they are."

He also noted that the study was done on a static snapshot of the internet so the data used is not entirely complete. "The connectivity is a little more dynamic and somewhat more complete and interconnected than the research would have indicated."