Kaspersky: We uploaded US documents but quickly deleted them

Sometime in 2014, a group of analysts walked into the office of Eugene Kaspersky, the ebullient founder of Russian cybersecurity firm Kaspersky Lab, to deliver some sobering news. The analysts were in possession of a cache of files belonging to the Equation Group, an extraordinarily powerful band of hackers that would later be exposed as an arm of the U.S. National Security Agency. But the analysts were worried; the files were classified.