Cisco discloses three router security problems

Cisco Systems is warning of three vulnerabilities within its Internet Operating System (IOS) software that could allow a denial-of-service (DoS) attack or let a hacker run arbitrary code on an affected switch router.

The company has published workarounds and issued an updated version of the software.

The three problems are:

-- TCP packet problem : A memory leak in certain versions of IOS could lead to a DOS attack, according to an advisory from the U.S. Computer Emergency Readiness Team. (CERT)

-- IPv6 router header vulnerability: IOS can fail to properly process IPv6 (Internet Protocol version 6) packets with specially-crafted routing heads, which could allow a DOS attack or the running of arbitrary code. IPv6 is a set of specifications that enables more IP addresses to be available on the Internet.

-- Crafted IP option vulnerability : This is a bug concerning how IOS processes IPv4 packets with a specially-crafted IP option, CERT said. It could also enable a DOS attack or the running of arbitrary code.

CERT wrote that all three vulnerabilities could cause a device to reload its OS. In that case, a secondary, sustained DOS condition could be caused since packets won't go through the device.

"Because devices running IOS may transmit traffic for a number of other networks, the secondary impacts of a denial of service may be severe," CERT said.