Note: This blog is a follow-up of our previous SolarWinds blog by our in-house threat intelligence team. You can read the first part here.

As we finish celebrating the end of 2020, security teams are returning to their (home) office to start preparations for the coming year. The daunting task of clearing that enormous email backlog will likely entail several difficult questions surrounding the SolarWinds compromise.

 If you didn’t have the chance to follow the latest developments on this case, here’s a wrap-up of the latest updates you should be aware of:

A Timeline of the Latest Update

SolarWinds Update

17 Dec 2020: The Cybersecurity and Infrastructure Security Agency (CISA) published an alert claiming that the threat actor behind this long-running campaign demonstrated exceptional patience, operational security, and technical sophistication. Consequently, removing this threat actor from compromised environments would be a “highly complex and challenging” task for security teams. The alert also reported that SolarWinds’ Orion hasn’t been the only initial access vector involved and that CISA was investigating for additional vectors and changes to TTPs.

18 Dec 2020: Microsoft published a blog asserting that the attackers had tested their ability to add code into SolarWinds product updates as early as October 2019. The blog also claimed that the threat actor took extensive steps to obfuscate their activities, such as ensuring placement on a victim’s network rather than in a malware sandbox, along with maintaining an unpredictable delay between different communications with the command and control (C2) servers. On top of this, the investigation led by security researchers discovered another malware affecting SolarWinds Orion; however, that could not be attributed to the same threat actor.

24 Dec 2020: FireEye released additional technical details on the “SUNBURST” vulnerability. This blog piece details the threat actor’s use of Domain Generation Algorithm (DGA) to generate target-specific subdomains for each affected domain, attempting to mimic legitimate SolarWinds protocol traffic, and limiting the amount of shared network infrastructure among victims. Furthermore, SUNBURST maintains an extensive array of functions and capabilities, allowing hands-on-keyboard attackers to perform several malicious actions. Adversaries could perform privilege escalation, reconnaissance on the network, data collection, and lateral movements to achieve their goal.

31 Dec 2020: SolarWinds released a security advisory confirming the removal of software builds affected by the SUNBURST vulnerability from the download section on their website. SolarWinds also claimed its internal investigations did confirm the presence of other non-Orion compromised products. However, following external claims on a new malware, another internal investigation uncovered the presence of a malware dubbed “SUPERNOVA” which impersonates SolarWinds products to require unauthorized access to customers’ networks. Both SUNBURST and SUPERNOVA vulnerabilities are fixed in the Orion Platform versions 2019.4 HF6 and 2020.2.1 HF2. Users can determine which Orion Platform version they are using here, and check which hotfix updates are installed here.

31 Dec 2020: Microsoft released an investigation update, in which it was confirmed that an internal audit did not provide any evidence of “access to production services or customer data”, or that Microsoft’s systems were leveraged for further attacks. Further examinations discovered unusual activities from several accounts, with one found to have been used to view, but not edit, a number of source code repositories. However, as Microsoft’s threat model assumes that attackers have knowledge of their source codes, an intruder viewing them “isn’t tied to elevation of risk”.

05 Jan 2021: The Federal Bureau of Investigation (FBI), the Office of the Director of National Intelligence (ODNI), the National Security Agency (NSA), and CISA released a joint statement claiming that “an Advanced Persistent Threat (APT) actor, likely Russian in origin, is responsible” of the recently discovered campaign against governmental and private organizations. Additionally, the statement affirmed that the attackers’ intentions were likely to conduct an intelligence gathering effort. 

The full scope of the campaign is still unclear and it may be broader than what originally believed. According to a New York Times article, the attackers may have exploited multiple layers of the supply chain to compromise approximately 250 organizations.  

What does this mean?

The most recent investigations have provided further evidence that a highly sophisticated threat actor has orchestrated this campaign with extensive resources and motivations. However, there was no new information that would force security teams to radically change how they would respond to this operation. SolarWinds’ customers should keep hunting for potential evidence of an intrusion in their environment in light of the latest technical details released. 

The security community at large is providing numerous free tools that security teams can use to detect potentially malicious activity in their environment—for example, CISA recently released “Sparrow” to help detect “possible compromised accounts and applications” linked to the SolarWinds compromise.

The scope of the operation mounted by the attackers should be an indication of the profound impact that supply chain attacks can have on affected organizations. Attackers often exploit trusted relationships with third parties to target weak points in the supply chain and bypass internal security measures. 

Consequently, even if not directly interested in the SolarWinds compromise, security teams are advised to perform risk assessments on their third party providers to ensure rigorous quality standards. Practices like monitoring their digital footprint and implementing hardening solutions could go a long way in responding to potential threats in a timely and effective manner. Security teams can also benefit from keeping an updated threat model to inform a risk-based approach to vulnerability management as new information is released.

SolarWinds comprise victims
SolarWinds compromise’s victims by sector (source: Microsoft)

Although official government bodies have indicated that a Russian APT is likely behind the SolarWinds compromise, their strategic objectives are still unclear. Understanding the full extent and goals of this campaign will be a long-lasting process. Intelligence gathering operations can serve a variety of purposes—ranging from privileged information extraction to Intelligence Preparation of the Battlefield (IPB)—and at this point in time, there’s simply not enough evidence to confirm one over the other. Consequently, security teams should focus their efforts in investigating their environment and looking for potential evidence of intrusion.

Where to go from here?

As we continue to upload our blogs as new updates come out, please refer to these resources for detection and mitigation instructions:

Since our first blog on the SolarWinds compromise, we’ve given our clients a proactive approach on the event with Public Intelligence alerts and Threat Profile , which include relevant indicators of compromise (IoCs), latest news, and event updates.

If you’re not a Digital Shadows (now ReliaQuest) client, setting up Google Alerts to monitor potential supply chain breach announcements could be a good way to remain updated on the latest relevant events. You can additionally trial our services, including access to an updated library of 200+ threat actors, tools and campaigns and a platform to continually monitor and assess your third-party risk.

If you are a Digital Shadows (now ReliaQuest) client  with access to ShadowSearch, we’ve prepared a list of queries that you can use to stay on top of details as they emerge:


type=[indicator feeds] AND “solarwinds”


(type=[blog posts] OR type=[intelligence incidents]) AND “solarwinds” AND date=[now-1M TO now]


“UNC2452” AND (type=[Blog posts] OR type=[Intelligence])


“APT29” AND (type=[Blog posts] OR type=[Intelligence])


(“solarwinds” OR “UNC2452”) AND (type=[Forum posts] OR type=[Chat messages] OR type=[Marketplace listings])


(“solarwinds” OR “UNC2452”) AND (type=[Vulnerabilities & Exploits]) date=[now-6M TO now]