Russian hackers reportedly exploited a vulnerability in Kaspersky Lab's software to steal sensitive cyberdefense data from a National Security Agency contractor. The incident, which occurred in 2015, involved a contractor who loaded classified information onto his personal computer in order to work at home. The information included hacking tools and other sensitive data that the NSA used to gather intelligence overseas. The contractor worked in the NSA's Tailored Access Operations unit, an elite hacking division in the agency.