The Sofacy group, also known as APT28 and Sednit, is a fairly well known cyber espionage group believed to have ties to Russia. Their targets have spanned all across the world, with a focus on government, defense organizations and various Eastern European governments. There have been numerous reports on their activities, to the extent that a Wikipedia entry has even been created for them.

http://researchcenter.paloaltonetworks.com/2016/02/a-look-into-fysbis-sofacys-linux-backdoor/