Core Internet technology is vulnerable to hackers, researchers find

Researchers found a serious security flaw that left core Internet technology vulnerable to hackers, prompting a secretive effort by international governments and industry experts in recent weeks to prevent global disruptions of Web surfing, e-mails and instant messages.

Experts said the flaw, disclosed Tuesday by the British government, affects the underlying technology for nearly all Internet traffic. Left unaddressed, they said, it could allow hackers to knock computers offline and broadly disrupt vital traffic-directing devices, called routers, that coordinate the flow of data among distant groups of computers.

"Exploitation of this vulnerability could have affected the glue that holds the Internet together," said Roger Cumming, director for England's National Infrastructure Security Coordination Centre.

The flaw affecting the Internet's "tranmission control protocol," or TCP, was discovered late last year by a computer researcher in Milwaukee, Paul "Tony" Watson, 36, who said he identified a method to reliably trick personal computers and routers into shutting down electronic conversations by resetting the machines remotely.

Routers continually exchange important updates about the most efficient traffic routes between large networks. Continued successful attacks against routers can cause them to go into a stand-by mode, known as "dampening," that can persist for hours.

Experts previously maintained such attacks could take between four years and 142 years to succeed because they require guessing a rotating number from roughly 4 billion possible combinations. Watson said he can guess the proper number with as few as four attempts, which can be accomplished within seconds.

"The biggest concern is (the effect on routers) because of the risk of bringing down the Internet or severely disrupting traffic on the Internet," Watson said.