PhotoAn analysis of federal records, which USA Today obtained through the Freedom of Information Act, shows that hackers were able to successfully compromise the computer networks of the Department of Energy 159 times between 2010 and 2014. This includes 19 successful attacks against the National Nuclear Security Administration, the DoE sub-branch responsible for overseeing the nation's stockpile of nuclear weapons.

One of those breaches had already been disclosed to the public: in July 2013, the DoE admitted to a “cyber incident” resulting in compromised personal data for “approximately 104,179” past and current DoE employees, contractors, and dependents.

What information was compromised in the other 158 breaches disclosed in USA Today's Freedom of Information request? That's not known – the DoE redacted it all from the FOI records. But it is known that, of those 159 successful cyberattacks, 53 of them were root compromises, which granted the hackers administrative privileges over DoE computer systems, and 90 of the intrusions were connected to the Office of Science, which is responsible for 10 federal energy laboratories.

A spokesman for the DoE said that the department “does not comment on ongoing investigations or possible attributions of malicious activity.”

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