Cisco Gear Subject to DoS Attack

Cisco Systems on Friday warned that a denial of service (DoS) vulnerability exists for its products.

The threat affects all Cisco products running the vendor's Internetwork Operating System (IOS). A DoS attack can be triggered if a hacker crafts a malicious TCP connection to a Telnet or reverse Telnet port of a Cisco device running IOS, according to a security advisory issued by Cisco, San Jose, Calif.

Telnet is a common way to control Web servers remotely.

If the vulnerability is exploited, network-based management connections to IOS-based Cisco routers could be blocked. However, data traffic through the routers would continue to flow.

Cisco is offering free software and technical workarounds at its Web site.The Internet Storm Center, Bethesda, Md., recommends remediation of the Cisco vulnerability as quickly as possible.