When FireEye disclosed details of the attack on SolarWinds in early December, in addition to the Sunburst backdoor, it mentioned a piece of malware named Supernova. However, further analysis has led researchers to believe that Supernova is not related to Sunburst.
Supernova has been described by Palo Alto Networks as a sophisticated, in-memory .NET web shell that can allow attackers to conduct reconnaissance and lateral movement, among other activities.