happened in less than a year, from the official in charge of defending the nuclear sites. it follows a destructive signal intelligence official. could this particular virus. >> don't know at this point. i don't know anyone that has done a real forensics. it probably speaks to an emerging class of problem that we call industrial control system problems, the ability to get into an embedded system that controls a turbine that controls a centerfuge and an engine. >> reporter: this attack, like the virus that hit the iranians last year may be a zero day exploit. like a patient zero case, it means the iranians may not have had any warning, hadn't seen anything like it before, and didn't know what to look for a.