NSA HQ

The United States tried to deploy a version of the Stuxnet computer virus to attack North Korea‘s nuclear weapons program five years ago but ultimately failed, according to people familiar with the covert campaign.

The operation began in tandem with the now-famous Stuxnet attack that sabotaged Iran’s nuclear program in 2009 and 2010 by destroying a thousand or more centrifuges that were enriching uranium. Reuters and others have reported that the Iran attack was a joint effort by U.S. and Israeli forces.

Like Iran, North Korea probably directs its centrifuges with control software developed by Siemens AG that runs on Microsoft Corp’s Windows operating system, the experts said. Stuxnet took advantage of vulnerabilities in both the Siemens and Microsoft programs.

But U.S. agents could not access the core machines that ran Pyongyang’s nuclear weapons program, said another source, a former high-ranking intelligence official who was briefed on the program.

The official said the National Security Agency-led campaign was stymied by North Korea’s utter secrecy, as well as the extreme isolation of its communications systems.

A spokeswoman for the NSA declined to comment for this story.

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