The U.S. government was successfully hit this year as part of a massive global cyberespionage operation, despite the National Security Agency and U.S. Cyber Command ramping up their “defend forward” strategy in recent years and going on offense around the world.

The Department of Homeland Security issued a governmentwide directive just before midnight on Sunday to purge agency networks of potentially compromised servers after discovering the Treasury and Commerce departments were victims of a monthslong cyberattack campaign suspected by many to be a Russian hacking effort.