Cisco products, including its PIX firewall, are subject to multiple vulnerabilities in Secure Shell (SSH) despite the fact problems with the protocol have been known about for almost a year.

The networking giant today issued a notice to customers which warns that by exploiting weaknesses "inherent" in SSH protocol version 1.5 "it is possible to insert an arbitrary commands into an established SSH session".

Attackers might also be able to "collect information that may help in brute force key recovery, or brute force a session key", the notice said.

Mark Read, a security consultant at MIS Corporate Defence Solutions, downplayed the risk posed by the bugs, which he said posed no immediate threat, and in any case depend on already having access to an internal network.

"In order to exploit these bugs you need to be able to sniff traffic or have already penetrated a firm's external box, which also happens to be a hub. This is easier said than done and would take a lot of skill certainly far beyond that needed to exploit a Microsoft glitch," said Read.

Read was puzzled why Cisco had issued a notice at this time. He said its been well known for the last nine months in the security community that version one of SSH was flawed.

SSH provides a secure way to remotely manage networked devices and a wide variety of Cisco kit is affected by the vulnerability. These include Cisco switches and routers running Cisco IOS software and supporting SSH, Catalyst 6000 LAN switches running CatOS as well as the networking giant's PIX Firewall.

Cisco has said its possible to limit the scope of the vulnerability by preventing, or having a control over, the interception of SSH traffic. It has also published a plan for the delivery of fixed software releases, and said upgrades to fix the problem should be available "free of charge".

Customers unsuccessful at obtaining fixed software through resellers are advised to contact the Cisco Technical Assistance Centre (TAC). ®

External Links

Cisco's security notice

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