The Inside Story of How Stuxnet Was Discovered
|If Iran had attacked US nuclear facilities with a computer virus,|
it would have been considered an act of war.
It was January 2010 when officials with the International Atomic Energy Agency (IAEA), the United Nations body charged with monitoring Iran's nuclear program, first began to notice something unusual happening at the uranium enrichment plant outside Natanz in central Iran.Inside the facility's large centrifuge hall, buried like a bunker more than fifty feet beneath the desert surface, thousands of gleaming aluminum centrifuges were spinning at supersonic speed, enriching uranium hexafluoride gas as they had been for nearly two years. But over the last weeks, workers at the plant had been removing batches of centrifuges and replacing them with new ones. And they were doing so at a startling rate. At Natanz each centrifuge, known as an IR-1, has a life expectancy of about ten years. But the devices are fragile and prone to break easily. Even under normal conditions, Iran has to replace up to 10 percent of the centrifuges each year due to material defects, maintenance issues, and worker accidents.
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In November 2009, Iran had about 8,700 centrifuges installed at Natanz, so it would have been perfectly normal to see technicians decommission about 800 of them over the course of the year as the devices failed for one reason or another. But as IAEA officials added up the centrifuges removed over several weeks in December 2009 and early January, they realized that Iran was plowing through them at an unusual rate.
What the inspectors didn't know was that the answer to their question was right beneath their noses, buried in the bits and memory of the computers in Natanz's industrial control room. Months earlier, in June 2009, someone had quietly unleashed a destructive digital warhead on computers in Iran, where it had silently slithered its way into critical systems at Natanz, all with a single goal in mind—to sabotage Iran's uranium enrichment program and prevent President Mahmoud Ahmadinejad from building a nuclear bomb.