The hackers who struck the power centers in Ukraine—the first confirmed hack to take down a power grid—weren’t opportunists who just happened upon the networks and launched an attack to test their abilities; according to new details from an extensive investigation into the hack, they were skilled and stealthy strategists who carefully planned their assault over many months, first doing reconnaissance to study the networks and siphon operator credentials, then launching a synchronized assault in a well-choreographed dance. —Inside the Cunning, Unprecedented Hack of Ukraine’s Power Grid - WIRED