Washington: Russian government-backed hackers stole highly classified U.S. cyber secrets in 2015 from the National Security Agency after a contractor put information on his home computer, two newspapers reported on Thursday.
As reported first by The Wall Street Journal, citing unidentified sources, the theft included information on penetrating foreign computer networks and protecting against cyber attacks and is likely to be viewed as one of the most significant security breaches to date.
In a later story, The Washington Post said the employee had worked at the NSA's Tailored Access Operations unit for elite hackers before he was fired in 2015.
The NSA declined to comment, citing agency policy "never to comment on our affiliates or personnel issues." Reuters was not able to independently verify the reports.
If confirmed, the hack would mark the latest in a series of breaches of classified data from the secretive intelligence agency, including the 2013 leaks of data on classified U.S. surveillance programs by contractor Edward Snowden.
Another contractor, Harold Martin, is awaiting trial on charges that he took classified NSA material home. The Washington Post reported that Martin was not involved in the newly disclosed case.
Citing unidentified sources, both the Journal and the Post also reported that the contractor used antivirus software from Moscow-based Kaspersky Lab, the company whose products were banned from U.S. government networks last month because of suspicions they help the Kremlin conduct espionage.