Microsoft says the cyberespionage campaign has hit U.S. and U.K. targets, relying on sheer volume and requiring only a single victim interaction.

The simultaneous actions targeted the Star Blizzard espionage operation, which went after government and civil society groups around the world.

The government-backed hackers exploited fake friends and family with spear-phishing lures, according to research published Wednesday.

Andrey Korinets and Ruslan Peretyatko are alleged to have played a key role in the FSB's efforts to meddle in U.S. and British politics.