Countdown to Zero Day: Stuxnet and the Launch of the World's First Digital Weapon

by Kim Zetter

  Then that May, the IAEA was suddenly gifted with a large cache of documents, of mysterious provenance, that further intensified concerns about Iran’s nuclear program.

  It began when Heinonen got a call from a woman with an American accent who said her name was Jackie. He suspected she was from the CIA but didn’t ask. She knew details about his investigation into Iran’s nuclear program and said that she had information that would be of interest to him. Heinonen was wary of being manipulated by the CIA, but agreed to meet her at a Starbucks.20

  When he arrived at the coffeehouse, a young Asian woman was waiting to speak with him. She told him she would arrange a meeting for him with two of the CIA’s moles who had been inside the Khan nuclear supply network and who could brief him about Khan’s dealings with Iran. She also said she had a stash of documents about Iran’s nuclear program that she wanted to show him. The documents came from a businessman in Tehran who had worked for the government in the steel and concrete industries—activity that took him to Natanz and Esfahan and put him in touch with the people behind Iran’s nuclear program. Somehow he had gained access to a large cache of highly sensitive documents about the nuclear program and had been passing them along to Germany’s intelligence agency, the BND. “Dolphin,” as the BND dubbed him, had planned to use the documents as a ticket to asylum in the West for him and his family. But before he could execute his plan, Iranian intelligence agents arrested him. His wife and children managed to flee across the border to Turkey, however, taking the documents with them.

  When Heinonen read the documents, he couldn’t believe his eyes. Dolphin’s cache laid out in a very concise manner a series of projects that purportedly composed Iran’s secret nuclear weapons program. They included the country’s ambitious plans to make its own nuclear fuel by mining uranium ore from a mine in southern Iran, then processing it to produce uranium concentrate (or “yellowcake”), and finally converting the yellowcake into uranium tetrafluoride and uranium hexafluoride gas. Uranium tetrafluoride can be used to make uranium metal, which can be used for nonweapons applications but also for bombs.21

  None of this alone was evidence of a nuclear weapons program. But the most alarming documents in the Dolphin stash were ones that described precision tests for detonating highly explosive materials. There were also sketches and instructions for building a reentry vehicle for Iran’s fleet of Shahab-3 missiles that would contain a heavy round object—suspiciously similar to a nuclear warhead—as well as a three-minute video showing a simulated explosion of a warhead at 1,970 feet, played to the cheesy Vangelis soundtrack from Chariots of Fire.22 A detonation at such a high altitude made no sense for releasing a chemical or biological weapon, Heinonen reasoned, so the warhead being designed must be intended for a nuclear weapon.23

  Were the documents authentic? Heinonen couldn’t be sure, but they corroborated other information the IAEA had been receiving from member states about Iran’s activities. If he was correct in his interpretation of the documents, then they were the most damning evidence yet that Iran was indeed working on a nuclear weapons program.

  The IAEA later confronted Iranian officials about the documents and demanded an explanation, but officials said the documents describing the explosives tests were just as applicable to conventional warheads as to nuclear ones and denied that the tetrafluoride project existed at all. They accused the IAEA of fabricating the documents to get sanctions passed against Iran and to build a case for justifying a US and Israel air strike against Natanz.24

  Just when it seemed that tension over its nuclear program couldn’t get any worse, Iran agreed again in late 2004 to suspend its uranium conversion plans at Esfahan as well as all of its other enrichment activities and to commit to formal talks about its nuclear program. The suspension agreement didn’t last very long, however. In June 2005, Mahmoud Ahmadinejad, the mayor of Tehran, was elected president of Iran, and government support for the suspension and talks began to erode. Iran’s nuclear program was becoming an issue of national pride, and hardliners in the government were beginning to view the suspension and talks as weak capitulation to the West. No matter what they did to appease the West it would never be enough, they said, because the real goal of Israel and the United States was to topple the Iranian regime.

  As the war in Iraq dragged on and the United States lost the upper hand there, Iranian leaders became bolder in their defiance. In August 2005, just two months after Ahmadinejad’s election, international talks over the program reached an impasse, and Iran announced it was revoking the suspension agreement.25 Iran wasted no time removing seals that the IAEA had placed on equipment at the Esfahan plant during the suspension, and proceeded with its plans to convert uranium oxide into uranium hexafluoride gas. Conditions went from bad to worse in December, when Ahmadinejad ignited a firestorm by declaring in a public speech that the Holocaust was a myth.26

  Things were spiraling out of control. Iran’s neighbors in the Middle East were so spooked by the growing tension between Iran and Israel that Kuwait’s Ministry of Health decided to install fifteen radiation-detection systems throughout the country and at border sites to provide early warning of any nuclear activity in the region.27 Efforts to gauge how close Iran was to being able to build a bomb, however, were scattershot. No one had a clear view of its covert program. But Iran didn’t actually have to build a nuclear weapon to be a threat. All it had to do was master the enrichment process and produce enough low-enriched uranium to make a bomb should it choose to. Once it reached this breakout point, Iran could perch on that threshold indefinitely—all the while maintaining truthfully that it possessed no nuclear weapons—until the day it decided to convert the enriched uranium into weapons-grade material and build a bomb. Estimates about how long it would take Iran to reach the breakout point varied. The US National Intelligence Estimate of 2005 concluded that Iran was six to ten years from having enough material to produce a bomb. But Israel was less optimistic. Officials there estimated it was closer to five years.28

  Enriching uranium is one of the most difficult processes to master in making nuclear weapons. It is a delicate undertaking in the best of circumstances, fraught with trial and error, and Iran had little experience doing it. Add to this the difficulties involved in manufacturing workable centrifuges, and it was easy to see why Iran’s program had taken so long to reach the point that it had. Indeed, it appeared that technicians at Natanz were still having problems with their centrifuges, as Ariel Levite, deputy director general of the Israel Atomic Energy Commission, told the United States in early 2006. It would later be revealed that some of the problems were due to sabotage of components that Iran had obtained from Turkey.29

  Regardless of the obstacles, in early 2006, Iran resumed enrichment at the pilot plant at Natanz. The move prompted Israeli officials to revise their previous estimate, saying now that Iran was just two to four years from nuclear weapons capability.30 They warned the United States that Iran must not be allowed to master its enrichment process or it would be “the beginning of the end.” Once that occurred, Iran would be able to enrich uranium in secret facilities anywhere in the country.31 Centrifuge plants, unlike other parts of the fuel cycle, didn’t require special facilities to operate. So once technicians worked out all of the kinks with the process, they could hide cascades of centrifuges anywhere they wanted—even in converted office buildings. “We know Iran is moving elements of its program right now,” Gideon Frank, director general of the Israel Atomic Energy Commission, warned US officials in early 2006.32 Factories able to produce parts for centrifuges were already “all over the place,” he said, and other parts of the nuclear program were being housed inside heavily fortified military facilities, where IAEA inspectors would not be able to examine them, and being sequestered underground where air strikes likely would not be effective.

  Then in May, Iranian officials announced that technicians at the pilot enrichment plant at Natanz had succeeded in enriching their first batch of uranium to 3.5 percen
t, using a full cascade of 164 centrifuges. This was followed by another announcement that technicians would finally begin installing the first of 3,000 centrifuges in one of the large underground halls. It appeared that Iran had finally overcome its difficulties, and that nothing, short of an air strike, could stop it now.

  Concerned that its ability to monitor Iran’s nuclear program was rapidly declining, the IAEA declared Iran in noncompliance with its safeguards agreement after years of being urged to do so by the United States. The UN Security Council adopted a resolution in July 2006, demanding that Iran suspend its enrichment by the end of August or face sanctions. Ahmadinejad refused. “Those who think they can use the language of threats and force against Iran are mistaken,” he said. “If they don’t realize that now, one day they will learn it the hard way.”33

  Western intelligence agencies suddenly noticed an uptick in Iranian efforts to secretly procure centrifuge components in Europe and elsewhere using a network of foreign and domestic front companies.34 They were “trying to buy like mad,” recalls David Albright of ISIS. They were seeking valves, pipes, and vacuum equipment, as well as components that could be used for missile development.35

  Rumors began swirling about plans for an air strike, but privately, Secretary of State Condoleezza Rice told the IAEA’s ElBaradei that she didn’t think it would come to this. Iran, she said, would surely “buckle.” But Iran wasn’t buckling.

  At the end of 2006, with no choice than to follow through on its threat, the UN Security Council adopted a resolution applying sanctions against Iran, banning the supply of materials and technology that could be used for nuclear development. Months later it voted on more sanctions to freeze the assets of individuals and organizations believed to be involved in the nuclear program.36 Still, Iran remained undeterred.

  In February 2007, Iranian officials announced to the IAEA that technicians at Natanz had already begun to install the first centrifuges in one of the underground halls. It had taken more than a decade for Iran to reach this point, but it had at last overcome all the obstacles—technological and manmade—that had been in its way. With nothing left to stop them, technicians had two cascades installed in one of the underground halls by the end of the month, and another two were in the final stages of installation. They had also transferred nine tons of uranium hexafluoride gas into the hall to begin enrichment.37

  By June 2007, 1,400 centrifuges were installed at Natanz and enriching uranium. All of the centrifuges were IR-1s, but technicians had also begun producing IR-2 centrifuges, the more advanced centrifuge based on Pakistan’s P-2 design. Iran had revived production of the IR-2s after its initial failure to produce rotors for the centrifuges.38 Iran was also developing even more advanced IR-4 centrifuges.39

  Tension between the United States and Israel flared. Israel accused the United States of dragging its feet with regard to Iran’s program and placing too much trust in sanctions and diplomatic efforts. Israeli prime minister Ehud Olmert warned in a public address that if Iran’s program wasn’t halted, Israel would act on its own. “Anyone who threatens us, who threatens our existence, must know that we have the determination and capability of defending ourselves,” he said. “We have the right to full freedom of action to act in defense of our vital interests. We will not hesitate to use it.”40

  But something happened in December 2007 to throw a wrench not only in US diplomatic efforts but in Israel’s attack plans as well. The US National Intelligence Estimate (NIE) came out that month with a startling conclusion about Iran’s nuclear program. It stated with “high confidence” that Iran did have a nuclear weapons program at one time but had halted the program back in the fall of 2003, following the US-led invasion of Iraq. This suggested that Iran was “less determined to develop nuclear weapons” than previously believed. NIEs, coordinated by the Office of the Director of National Intelligence, are based on information gleaned from US and foreign intelligence. But this one seemed to contradict what Adm. Michael McConnell, director of national intelligence, had told a Senate committee just months before. “We assess that Tehran seeks to develop nuclear weapons and has shown greater interest in drawing out the negotiations rather than reaching an acceptable diplomatic solution,” he told the Senate Armed Services Committee the previous February.41

  Although the NIE report also noted that Iran could reverse the decision to halt its weapons program at any point, and a classified version of it discussed evidence that didn’t make it into the public version—that Iran might still have more than a dozen other covert nuclear facilities doing illicit enrichment and weapons development—the report threatened to weaken the case for sanctions against Iran and for military action.42 US Defense Secretary Robert Gates, who opposed an air strike, nonetheless questioned the report’s conclusion. During a congressional hearing to discuss it, he warned that Iran was engaged in suspicious procurement activities that suggested its nuclear plans were much more organized and directed than the NIE suggested. Gates wasn’t the only one who disagreed with the NIE conclusion. Privately, German officials told the United States that their own intelligence indicated that Iran still had a weapons program, and Israeli officials also said they had information indicating that although Iran had halted its weapons program in 2003, it had revived it in 2005.43

  As the sun set on 2007, Iran had 3,000 centrifuges installed at Natanz and was planning to double that number in the next year. Experts estimated that 3,000 P-1 centrifuges alone could already produce enough low-enriched uranium for a bomb in less than a year, if Iran decided to further enrich it.44

  It seemed there was nothing anyone could do to halt the enrichment program now without risking a war.

  Or was there?

  While tensions over the enrichment program approached the breaking point, an alternative plan was being secretly set in motion. As Iranian technicians congratulated themselves over the progress they’d made at Natanz and were making preparations to expand the operation, a digital weapon was silently unleashed on computers at the plant with a clear-cut mission embedded in its code. With hundreds of rapidly spinning centrifuges in its sights, the precision weapon stealthily and decisively made its way straight to its target.

  * * *

  1 Khatami was speaking in Tehran on February 9, 2003, during a meeting between the Ministry of Science, Research and Technology and university chancellors. Parts of his speech were reported at: iranwatch.​org/​library/​government/​iran/​iran-​irna-​khatami-​right-​all-​nations-​nuclear-​energy-​2-​9-​03.

  2 The thirty-five member countries on the IAEA’s Board of Governors can vote to open an inquiry or refer a country to the UN Security Council for sanctions.

  3 Prior to the war, the IAEA’s deputy director in charge of compliance told Leonard Weiss, staff director of the Senate Committee on Governmental Affairs, that not only was Iraq’s cooperation with the IAEA exemplary but that the IAEA had no hint from anyone that Iraq was doing anything untoward. See Leonard Weiss, “Tighten Up on Nuclear Cheaters,” Bulletin of Atomic Scientists 47 (May 1991): 11.

  4 David Albright and Mark Hibbs, “Iraq’s Nuclear Hide and Seek,” Bulletin of Atomic Scientists 47 (September 1991): 27.

  5 Douglas Frantz and Catherine Collins, The Nuclear Jihadist: The True Story of the Man Who Sold the World’s Most Dangerous Secrets (New York: Free Press, 2007), 188.

  6 In 2004, Iran agreed to sign the Additional Protocol but didn’t ratify it. Later, in 2006, after the IAEA referred Iran to the UN Security Council for noncompliance with its safeguards agreement, Iran retaliated by announcing it would no longer adhere to the Protocol.

  7 David Albright, Peddling Peril: How the Secret Nuclear Trade Arms America’s Enemies (New York: Free Press, 2010), 192.

  8 David Albright and Corey Hinderstein, “The Iranian Gas Centrifuge Uranium Enrichment Plant at Natanz: Drawing from Commercial Satellite Images,” ISIS, March 14, 2003, available at isis-​online.​org/​publications/​iran/​natanz03_02.​html
. See also IAEA Board of Governors, “Implementation of the NPT Safeguards Agreement in the Islamic Republic of Iran” (report, June 6, 2003), 6.

  9 The uranium in question included uranium hexafluoride, uranium tetrafluoride, and uranium oxide.

  10 US satellite imagery had captured images of trucks visiting the site, suggesting that Iran had hauled away evidence before the inspectors arrived. See Frantz and Collins, Nuclear Jihadist, 293.

  11 IAEA, “Tools for Nuclear Inspection,” a two-page pamphlet published by the agency’s Division of Public Information, which describes the environmental sampling process. Available at iaea.​org/​Publications/​Factsheets/​English/​inspectors.​pdf.

  12 IAEA Board of Governors, “Implementation of the NPT Safeguards Agreement in the Islamic Republic of Iran” (report, November 10, 2003), 6–7.

  13 Sharon Squassoni, “Iran’s Nuclear Program: Recent Developments” (CRS Report for Congress, November 23, 2005), 3.

  14 The Institute for Science and International Security maintains a comprehensive page that details Iran’s laser enrichment activity. It’s available at isisnucleariran.​org/​sites/​by-​type/​category/​laser-​enrichment.

  15 The information comes from a transcript of an announcement made by NCRI spokesman Alireza Jafarzadeh. “Iran-Nuclear: Iranian Regime’s New Nuclear Sites,” available at ncr-​iran.​org/​en/​news/​nuclear/​568-​iran-​nuclear-​iranian-​regimes-​new-​nuclear-​sites.