An Israeli security agency hacked into Russian antivirus firm Kaspersky Lab in 2015, providing the crucial evidence required to ban the company from providing services to the US government, according to a report. While the Israeli spies were inside Kaspersky’s systems, they observed Russian spies in turn using the company’s tools to spy on American spies. On Sept. 13, the Department of Homeland Security ordered all federal executive branch agencies to stop using Kaspersky products, giving agencies 90 days to remove the software. That directive, which some officials thought was long overdue, was based, in large part, on intelligence gleaned from Israel’s 2014 intrusion into Kaspersky’s corporate systems. It followed months of discussions among intelligence officials, which included a study of how Kaspersky’s software works and the company’s suspected ties with the Kremlin.