NewsHour's Spencer Michels reports from a Las Vegas hacker conference on governmental efforts to stop online tampering that could affect critical infrastructure. Attendees at the DefCon hacker convention explain the United State military's reliance on networks and their extreme vulnerabilities to cyber attack. Michael Hayden, who was director of both the CIA and the National Security Agency, says of the attacks, "If you do something in the cyber-domain, something happens in physical space. This is not just a video game."