Router bug threatens 'internet backbone'

A critical software bug affecting many key internet routers could be used to derail net traffic, computer experts have warned.

Routers are the hubs of the internet, directing traffic to its destination. The software flaw affects the most common internet routers, those running the Cisco IOS operating system.

Repeatedly sending specially crafted data packets to a vulnerable router will cause it to attempt to restart over and over again, making it unavailable to direct legitimate traffic.

"This is basically the backbone to the internet," says Gunter Ollman, a consultant with Internet Security Systems in the UK. "Just about every single major organisation will be running Cisco routers at critical part of their infrastructure."

Ollman also told New Scientist that forcing a router to restart could cause it to incorrectly direct traffic even after it has begun operating again. So far, no tools designed to take advantage of the flaw have been created, but he says it may not be long until example code is posted online.

An advisory issued by Cisco recommends updating its routers' software to the latest version in order to protect them against possible attack.