Lynn felt compelled to quit his job Wednesday morning so that he could give the talk because the Cisco security issues are of vital importance to the Internet's health. "This is the right thing to do," he said, speaking Wednesday to Black Hat attendees, who punctuated his talk with applause. "When you attack the router, you gain control of the network."
Lynn described a now-patched flaw in the Internetwork Operating System (IOS) software used to power Cisco's routers, and to describe the steps he used to gain control of a router. Although Cisco was informed of the flaw by ISS, and patched its firmware in April, users running older versions of the company's software are at risk, he said.