The new 2014 date of the incident is of interest because Kaspersky only announced its discovery of an espionage campaign by the Equation Group in February 2015. At that time, Reuters cited former NSA employees who said that Equation Group was an NSA project.
Kaspersky's Equation Group report was one of its most celebrated findings, since it indicated that the group could infect firmware on most computers. That gave the NSA almost undetectable presence.
Shlychkova said the American machine's files were found before the big Equation Group announcement but after Kaspersky had discovered Equation software on a machine in the Middle East. She said that occurred in March 2014.
Democratic Senator Jeanne Shaheen, who led calls in the U.S. Congress to purge Kaspersky products from federal government networks, on Wednesday sent a letter to DHS acting Secretary Elaine Duke and Director of National Intelligence Dan Coats, urging the U.S. government to declassify information about Kaspersky products.
The step was necessary, Shaheen wrote, "to allow the American people to make informed decisions about risks to their privacy and security."
Also on Tuesday, Democratic Senator Claire McCaskill sent a separate letter to DHS asking what was being done to ensure federal agencies were complying with the ban on Kaspersky products.
Kaspersky's consumer anti-virus software has won high marks from reviewers.
The company said Monday it would submit the source code of its software and future updates for inspection by independent parties.
(Additional reporting by Dustin Volz; Editing by Jim Finkle and Lisa Shumaker)
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