In October 2018, ESET published a report describing a set of activity they called GreyEnergy, which is believed to be a successor to BlackEnergy group. BlackEnergy (a.k.a. Sandworm) is best known, among other things, for having been involved in attacks against Ukrainian energy facilities in 2015, which led to power outages. Like its predecessor, GreyEnergy malware has been detected attacking industrial and ICS targets, mainly in Ukraine.

https://ics-cert.kaspersky.com/reports/2019/01/24/greyenergys-overlap-with-zebrocy/