Although Cisco and Internet Security Systems had abruptly cancelled a planned technical talk and demo at the Black Hat Conference to reveal how unpatched Cisco routers can be remotely compromised, the researcher who had originally uncovered the problem went ahead with the talk anyway, igniting a spate of lawsuits against himself and the Black Hat Conference.

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Michael Lynn, the research analyst at ISS who was asked to resign after his presentation detailing how an attacker can exploit flaws in unpatched Cisco routers to gain total control over them, said he felt compelled to reveal the information because “I felt I had to do what’s right for the country and the national infrastructure.”

Cisco and ISS, claiming it was premature to release the research, saw it differently and immediately filed a lawsuit aimed at compelling him not to discuss the subject further. The Black Hat Conference was also served with a lawsuit by the two companies for allowing Lynn to discuss the exploits associated with Cisco routers.

Black Hat CEO Jeff Moss yesterday said he felt trapped in the middle. “Michael Lynn said he was going to discuss VoIP,” said Moss. “I can’t control a speaker who changes his topic in the middle of a presentation.”

Told by ISS not to discuss the Cisco router exploit, Lynn did begin his presentation at Black Hat on Wednesday with a substitute presentation on VoIP. But the boos from the audience which had come to hear the original topic entitled “The Holy Grail: Cisco IOS Shellcode and Remote Execution,” induced him to switch to the original scheduled topic: the research he carried out at ISS that shows how an attacker can completely take control of a Cisco router through a variety of buffer-overflow attacks and shellcode exploits.

While this type of attack is common against unpatched servers today - several destructive Internet worms in past years have used buffer-overflow attacks to take over Microsoft-based servers - this was believed to be the first demonstration of a buffer-overflow attack against Cisco routers.