Russia-tied group known as Turla is targeting government organizations using custom malware. Turla has outfitted a trio of backdoors with new C2 tricks and increased interop, as seen in an attack on a European government. Accenture researchers observed a recent campaign against a foreign government in Europe that ran between June and October. The upgrades revolved around creating built-in redundancies for remote communication, to allow different re-entry points should one of them be blocked. Backdoors include the HyperStack backdoor, Kazuar and Carbon.
Source: https://threatpost.com/russian-espionage-custom-malware/160673/