Cisco Systems after suing a security researcher who demonstrated a vulnerability in Cisco routers. Michael Lynn gave a talk at the 2005 Black Hat conference in Las Vegas in defiance of Cisco and Internet Security Systems, the company he quit to be able to give the talk. were selling well at DefCon, the hacker event that comes after Black Hat. Lynn settled with Cisco, barring him from further discussing the matter. His presentation, however, appeared on various Web sites, which Cisco .