BERLIN (AP) — When machines at a nuclear plant in Iran suddenly began spinning out of control six years ago, suspicion quickly fell on the United States and Israel, especially after a sophisticated virus was found that appeared to have been tailored to sabotage a key process in the enrichment of weapons-grade uranium.
Computer security experts dubbed the virus Stuxnet, describing it as the most powerful cyberweapon the world had yet seen. While the attack on the Natanz plant appeared to have met its immediate objective — to disrupt Iran's nuclear weapons program — the emergence of Stuxnet was soon compared to the dropping of the first atomic bomb on Hiroshima in 1945 for its ability to change the course of warfare.
A broad public debate about the use of cyberweapons has yet to happen, however, although every modern society is vulnerable to attacks on its critical infrastructure, says Alex Gibney, an Academy Award-winning documentary maker who spent years investigating the Stuxnet case for his new film, "Zero Days."
The movie, which premieres at the Berlin Film Festival on Wednesday, traces the origins of Stuxnet to joint U.S.-Israeli efforts to foil Iran's nuclear weapons program without resorting to airstrikes. But interviews with past and present intelligence officials in both countries soon met with a wall of silence that frustrated Gibney.
"Obviously the Manhattan Project (to develop the first U.S. atomic bomb) was a secret project, but when the bombs when off in Hiroshima and Nagasaki nobody said 'What bombs? Did bombs drop? We're shocked,'" he said.
Even after it became clear that other countries had not only obtained copies of Stuxnet but used parts of it in attacks, and the virus was spreading through computer systems in the United States, the U.S. government largely refused to engage in a debate on the pros and cons of cyberwarfare, said Gibney. "You would expect people to keep covert operations a secret but once they're blown, and particularly when they seem to cross over into so much physical destruction, at what point does it become almost nonsensical to not engage about those subjects?"
Unlike the case of former NSA contractor Edward Snowden, who approached journalists with classified information about U.S. electronic surveillance programs, Gibney said finding someone who would talk was "a long slog."
"I talked to some friends of mine who had been in the Obama administration and there was a sense of pretty extraordinary fear of even talking off the record about this topic," he said. "It was toxic. So it was really a problem, this one."
Eventually some in the intelligence community came forward, according to Gibney. Their identities remains hidden throughout the film, masked by an actress who voices their words.
One, a purported NSA employee, confirms the agency "did Stuxnet." The anonymous source also describes the operation — known internally as "Olympic Games" — as small compared to wider contingency plans for a cyberattack on Iran known as "Nitro Zeus."
The CIA declined to comment on the claims made in the film, some of which have been previously reported by the New York Times and the Jerusalem Post. It referred questions to the Office of the Director of National Intelligence, which didn't immediately respond to a request for comment.
Some experts believe Stuxnet helped spur negotiations toward last year's nuclear accord with Iran. Gibney thinks the blowback resulting from the release of such a sophisticated cyberweapon outweighs the benefits. With Russia, China, North Korea and Iran now believed to be among the countries with major cyberarmies, he thinks it's time to talk about the implications of a free-for-all in the field of electronic warfare.
"In a world that's so interconnected, if hospitals go down, if water filtration systems go down, if electricity goes down, suddenly in the modern world those effects can be catastrophic," Gibney told The Associated Press.
Still, the history of international accords to limit the use of nuclear, biological and chemical weapons offers some hope, he said.
"One thing we know about technology, and one thing we know about agreements is that over time you learn. You learn how to understand and defend against these weapons, and also how to figure out how to regulate their use," he said.