On December 13, 2020, FireEye published a blog post detailing a supply chain attack leveraging Orion IT, an infrastructure monitoring and management platform by SolarWinds. In parallel, Volexity published an article with their analysis of related attacks, attributed to an actor named “Dark Halo”. FireEye did not link this activity to any known actor; instead, they gave it an unknown, temporary moniker – “UNC2452”.
This attack is remarkable from many points of view, including its stealthiness, precision targeting and the custom malware leveraged by the attackers, named “Sunburst” by FireEye.
In a previous blog, we dissected the method used by Sunburst to communicate with its C2 server and the protocol by which victims are upgraded for further exploitation. Similarly, many other security companies published their own analysis of the Sunburst backdoor, various operational details and how to defend against this attack. Yet, besides some media articles, no solid technical papers have been published that could potentially link it to previously known activity.