Cisco software vulnerable to attack

CHICAGO: Cisco Systems Inc., the world's largest maker of equipment that directs Internet traffic, said that it has warned customers of a software flaw that could allow attackers to stop the flow of data through its routers.

The company has posted a security advisory and software fix on its Web site, and said it was not aware of any attacks.

'Through internal testing, Cisco has discovered that devices running Cisco IOS software may be susceptible to a denial-of-service attack,' Cisco spokesman Jim Brady said. 'To address this, Cisco has created an IOS software fix ... to minimize the risk of potential network attacks.'

IOS is the software on which most of Cisco's network hardware operates. A router is a machine that directs information and data on a communications network.

Attackers could send a 'rare sequence' of information packets directly to a Cisco device that could cause the router to believe its input queue is full, causing the device to stop processing traffic, the company said on its online advisory. In that case, the device must be rebooted to clear the queues.

SG Cowen said in a research note that such bugs are discovered from time to time and Cisco's responsiveness mitigates any issues, resulting in little damage to sales.

Brady said the company has contacted customers, including Internet service providers, corporations, and government, academic and Internet security organizations regarding the problem.

© Reuters