Cisco's fix for flaw runs into problems

Network equipment maker Cisco Systems warned Thursday that a previous fix for a vulnerability in the secure shell (SSH) module used in many of its devices actually causes an instability that could make the operating system freeze. In an advisory, the networking giant said all routers and switches running the company's homegrown operating system, Cisco IOS, and the CatOS could be affected if a hacker scans the system for an SSH vulnerability found last fall.

Both the Cisco PIX Firewall family and the Cisco 11000 Content Service Switch family are vulnerable.