Drovorub, a joint advisory from the NSA and the FBI reveals, is being employed by the Russian General Staff Main Intelligence Directorate (GRU) 85th Main Special Service Center (GTsSS) military unit 26165, which is better known as the cyber-espionage group APT 28 (Fancy Bear, Pawn Storm, Strontium, Sednit, Tsar Team). APT 28 is believed to…