Russia apparently has executed the most sophisticated and potentially most dangerous cyber-attack in history on the U.S. Government and private sector, penetrating the defenses of even the Cyber and Infrastructure Security Agency (CISA)—that is supposed to be the chief guardian against such threats to U.S. critical infrastructures. For at least 9 months, cyber-spies roamed undetected through: the National Nuclear Security Administration (responsible for U.S. nuclear weapons); the Department of Energy and Federal Energy Regulatory Commission (responsible for protecting national electric grids); defense contractors designing the nation’s most advanced weapons; and 18,000 other government and corporate victims. Still unknown is the scale and depth of the damage.