Ukraine energy company Ukrenergo suffered a severe power outage that affected the North substation at Pivnichna in December 2016. The incident caused blackouts in the city of Kiev and neighboring regions. Experts are still investigating to establish a timeline of events and identify the entry point of the hackers. The company is working to secure its system by implementing organizational and technological measures that would make its systems resilient to further attacks. Experts don’t exclude that the threat could still be inside the target network in a dormant state.”]
Source: https://securityaffairs.co/wordpress/55474/hacking/power-outage-2015-ukraine.html