ceios/database/BlackEnergy 2015 Ukranian electricity grid disruption/Summary of operation

On the 23rd of December, 2015, BlackEnergy and KillDisk malware rendered 225,000 Western Ukrainian residents were left without power for up to six hours via a hack of three Ukrainian energy distribution companies. 
When power was restored, the companies performed under constrained operations. 
The computer systems were hacked initially through spearphishing emails. 
BlackEnergy malware was used to steal user credentials, perform reconnaissance activities, and was then likely used to disrupt the transmission and distribution substation within the Ukrainian power grid. 
KillDisk was used at the conclusion of the operation to delete computer event logs and other files before rendering the infected computers inoperable.