Tuesday, February 15, 2011

The Cyberweapon that Could Take Down the Internet

Via NewScientist.com -

A new cyberweapon could take down the entire internet – and there's not much that current defences can do to stop it. So say Max Schuchard at the University of Minnesota in Minneapolis and his colleagues, the masterminds who have created the digital ordnance. But thankfully they have no intention of destroying the net just yet. Instead, they are suggesting improvements to its defences.

Schuchard's new attack pits the structure of the internet against itself. Hundreds of connection points in the net fall offline every minute, but we don't notice because the net routes around them. It can do this because the smaller networks that make up the internet, known as autonomous systems, communicate with each other through routers. When a communication path changes, nearby routers inform their neighbours through a system known as the border gateway protocol (BGP). These routers inform other neighbours in turn, eventually spreading knowledge of the new path throughout the internet.

A previously discovered method of attack, dubbed ZMW – after its three creators Zhang, Mao and Wang, researchers in the US who came up with their version four years ago – disrupts the connection between two routers by interfering with BGP to make it appear that the link is offline. Schuchard and colleagues worked out how to spread this disruption to the entire internet and simulated its effects.

Surgical strike

The attack requires a large botnet – a network of computers infected with software that allows them to be externally controlled: Schuchard reckons 250,000 such machines would be enough to take down the internet. Botnets are often used to perform distributed denial-of-service (DDoS) attacks, which bring web servers down by overloading them with traffic, but this new line of attack is different.

"Normal DDoS is a hammer; this is more of a scalpel," says Schuchard. "If you cut in the wrong places then the attack won't work."


Meltdown not expected

So is internet meltdown now inevitable? Perhaps not. The attack is unlikely to be launched by malicious hackers, because mapping the network to find a target link is a highly technical task, and anyone with a large enough botnet is more likely to be renting it out for a profit.

An alternative scenario would be the nuclear option in a full-blown cyberwar – the last resort in retaliation to other forms of cyberattack. A nation state could pull up the digital drawbridge by adjusting its BGP to disconnect from the internet, just as Egypt did two weeks ago. An agent in another country could then launch the attack, bringing down the internet while preserving the attacking nation's internal network.

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