. >> by the fall of 2010, the consensus was that iran's top secret uranium enrichment plant at natanzas the target and that stuxnet was a carefully constructed weapon designed to be carried into the plant on a corrupted laptop or thumb drive, then infect the system, disguise its presence, move through the network, changing computer code, and subtly alter the speed of the centrifuges without the iranians ever noticing. sabotage by software. >> stuxnet's entire purpose is to control centrifuges, to make centrifuges speed up past what they're meant to spin at and to damage them. certainly it would damage the uranium enrichment facility, and they would need to be replaced. >> if the centrifuges were spinning too fast, wouldn't the operators at the plant know that? >> stuxnet was able to prevent the operators from seeing that on their screen. the operators would look at the screen to see what's happening with the centrifuges, and they wouldn't see that anything bad was happening. [ticking] >> coming up, the danger of cyber warfare. >> you don't need many billions. you just need a couple of

the agency says that 180 of the so-called ir-2m centrifuges have been installed in natanz in central iran. they are capable of enriching uranium three times faster than other devices iran is using. the nuclear watchdog says that iran has so far refined 280 kilograms of uranium to a fissile purity of 20%. the iaea reports that 167 kilograms of the uranium could be used to develop nuclear weapons if iran has the technology to enrich it to more than 90% purity. this new assessment is likely to intensify criticism of iran among western nations. representatives of five permanent u.n. security council member nations and germany are due to hold talks with iran next week in kazakhstan concerning its nuclear program. >>> researchers in japan report a significant discovery in the fight against alzheimer's disease. they say they've identified part of the mechanism behind the pathology. the scientists used induced stem cells also known as ips cells that can be programmed to develop into any type of cell. associate professor haruhisa inoue leads the project at kyoto university for cell research a

look at this photo of president ahmadinejad in iran's nuclear facility in natanz. >> right behind him is an american transducer looking exactly like this thing. >> yes, the iranians were trying to acquire these transducers. >> one reason it's so hard to enforce the sanctions is that many items iran wants are sold for non-military uses, like this little widget-- a triggered spark gap. >> the triggered spark gap can be utilized in a lithotripter, which is a machine, a medical device, that can break up kidney stones. and it's also used to detonate a nuclear weapon. >> so this is the typical dual use item. >> a very scary dual use item. >> after you catch someone, have you been able to flip them? >> absolutely. >> and have you been able in this way to sabotage some of the things you send over? in other words, send over faulty stuff that'll break down. >> i can't comment on anything like that. [chuckles] up next, an iranian is arrested after buying sensitive equipment from the u.s. >> you ended up selling one of your devices to iran. >> by accident, certainly. >> did they tell you it was g

atomic energy agency" reported iran is installing advanced, uranium- enriching centrifuges at its natanz nuclear facility, a step the united states called provocative. >> sreenivasan: chuck hagel was sworn in today as the new secretary of defense, with federal budget cuts topping his agenda. the former republican senator from nebraska addressed pentagon employees who will have to manage some $46 billion in reductions starting friday. >> we need to figure this out. you are doing that. you have been doing that. we need to deal with this reality. we've got ahead of us a lot of challenges. they are going to define much of who we are, not this institution only but our country. >> sreenivasan: hagel won senate confirmation yesterday, despite the opposition of most of his fellow republicans. he succeeds leon panetta, who had served in the top pentagon job since july of 2011. white house officials conceded today it's unlikely the government will avoid those looming, automatic budget cuts. a spokesman said president obama will meet friday with congressional leaders, but there was no indication th