kevin mandia says even big corporations with sophisticated i.t. departments are no match for the dozens of countries that now have offensive cyber-war capabilities. >> mandia: all advantage goes to the offense in cyber. it just does. on the defensive side, you have to say, "i must defend all 100,000 machines, all 50,000 employees." the offensive side thinks, "i only need to break into one and i'm on the inside." >> kroft: and any company or any corporation is as strong as its weakest link. >> mandia: in a way, yes, in security. the nation-state threat actors, or hackers, target human weakness, not system weakness. >> kroft: and there's no shortage of weaknesses. most company employees are allowed to browse online or visit facebook on corporate computers. and many take them home for personal use. all it takes to contaminate a network is for one person to file that looks realistic, like an adobe flash player update or an email that pretends to be from apple support. and then what happens when they click on them? >> mandia: they compromise their machi