Nghia Hoang Pho, 67, of Ellicott City, Maryland, pleaded guilty to willful retention of national defense information, according to federal law enforcement officials.
The guilty plea said that between 2010 and March 2015, Pho removed and retained at his home paper and digital copies of U.S. government documents and writings containing national defense information.
Starting in April 2006, he worked as a developer in the National Security Agency's Tailored Access Operations unit, which is involved in cyber operations.
The charges carry a maximum sentence of 10 years in prison, followed by three years of supervised release, but prosecutors are recommending he serve eight years, according to his attorney, Robert Bonsib.
Pho, who was born in Vietnam and is a naturalized U.S. citizen, is free pending his sentencing, which is set for April 6, Bonsib said. He declined to give further details about the case.
The New York Times quoted unnamed government officials as saying Pho took the classified material home to assist him in reworking his resume. The officials told the newspaper that Pho's home computer was using antivirus software made by Kaspersky Lab, a top Russian software company, and that Russian hackers are thought to have exploited the software to steal the documents.
Bonsib declined to answer questions about Kaspersky.
The guilty plea was announced by Stephen Schenning, acting U.S. attorney for the District of Maryland; Dana Boente, acting assistant attorney general for national security; and Gordon Johnson, special agent in charge of the FBI's Baltimore Field Office.
NSA has suffered a series of setbacks in recent years. Most notably, former NSA contractor Edward Snowden disclosed a cache of classified material in 2013 exposing U.S. government surveillance programs.
In August 2016, Harold Thomas Martin III, 51, of Glen Burnie, Maryland, was arrested by the FBI after federal prosecutors said the former NSA contractor illegally removed highly classified information and stored the material in his home and car.
Reality Winner, 25, a former Air Force linguist who worked as an NSA contractor at a facility in Augusta, Georgia, was charged in June with copying a classified U.S. report and mailing it to a news organization.
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