SAN FRANCISCO -- RSA CONFERENCE 2013 -- FBI director Robert Mueller in his keynote address here Thursday cited the case of nabbing LulzSec leader "Sabu" as an informant for the bureau as a key example of how cybersecurity is not just about reducing vulnerabilities, but also catching the bad guys behind the attacks.

"We must remember that behind every intrusion there is an individual -- not a computer, but a criminal -- responsible for that intrusion. We must remember that cybersecurity is not just defending the ones and the zeros," Mueller said in his keynote.

"We must identify and deter the persons behind those computer keyboards. And once we identify them -- be they state actors, organized criminal groups or 18-year-old hackers -- we must devise a response that is effective, not just against that specific attack, but for all similar illegal activity," he said.