The December 2015 Ukraine power grid cyberattack took place on 23 December 2015 and is considered to be the first known successful "cyberattack on a "power grid. Hackers were able to successfully compromise information systems of three energy distribution companies in "Ukraine and temporarily disrupt electricity supply to the end consumers.
Most affected were consumers of «Prykarpattyaoblenergo» ("Ukrainian: Прикарпаттяобленерго; servicing "Ivano-Frankivsk Oblast): 30 substations were switched off, and about 230 thousand people were left without electricity for a period from 1 to 6 hours.
At the same time consumers of two other energy distribution companies, «Chernivtsioblenergo» ("Ukrainian: Чернівціобленерго; servicing "Chernivtsi Oblast) and «Kyivoblenergo» ("Ukrainian: Київобленерго; servicing "Kyiv Oblast) were also affected by a cyberattack, but at a smaller scale. According to representatives of one of the companies, attacks were conducted from computers with IP addresses allocated to the "Russian Federation.
The cyberattack was complex and consisted of the following steps: