https://www.fireeye.com/blog/threat-research/2020/12/evasive-attacker-leverages-solarwinds-supply-chain-compromises-with-sunburst-backdoor.html
 

There's an emerging story on the execs of Solarwinds that will come out soon, on "what they knew, and when they knew it." 

This is an attack on a scale that has never, ever happened before. Solarwinds is a company that manages the IT infrastructure of its clients - and the attack on Solarwinds means that the attackers could have used Solarwinds as a jumping-off point to load attacks onto the clients of Solarwinds. The clients of Solarwinds is a who's who of large US/multi-national business, governments at the Federal, state, county and city level, and a number of military segments.