NOBELIUM Cyberattack : New sophisticated email-based attack
Microsoft Threat Intelligence Center (MSTIC) has uncovered a wide-scale malicious email campaign operated by NOBELIUM, the threat actor behind the attacks against SolarWinds, the SUNBURST backdoor, TEARDROP malware, GoldMax malware, and other related components. The campaign, initially observed and tracked by Microsoft since January 2021, evolved over a series of waves demonstrating significant experimentation. On May 25, 2021, the campaign escalated as NOBELIUM leveraged the legitimate mass-mailing service, Constant Contact, to masquerade as a US-based development organization and distribute malicious URLs to a wide variety of organizations and industry verticals.
NOBELIUM has historically targeted government organizations, non-government organizations (NGOs), think tanks, military, IT service providers, health technology and research, and telecommunications providers.
Maintaining persistence is critical for any threat actor after gaining access to a network. In addition to the backdoor in the SolarWinds software, NOBELIUM has been observed using stolen credentials to access cloud services like email and storage, as well as compromised identities to gain and maintain access to networks via virtual private networks (VPNs) and remote access tools. Microsoft assesses that the newly surfaced pieces of malware were used by the actor to maintain persistence and perform actions on very specific and targeted networks post-compromise, even evading initial detection during incident response.
Due to the fast-moving nature of this campaign and its perceived scope, We encourages organizations to investigate and monitor communications matching characteristics described in this article.
Indicators of compromise (IOC)
This attack is still active, so these indicators should not be considered exhaustive for this observed activity. These indicators of compromise are from the large-scale campaign launched on May 25, 2021.