New Blog Post | FoggyWeb: Targeted NOBELIUM malware leads to persistent backdoor



FoggyWeb: Targeted NOBELIUM malware leads to persistent backdoor | Microsoft Security Blog

Microsoft continues to work with partners and customers to track and expand our knowledge of the threat actor we refer to as NOBELIUM, the actor behind the SUNBURST backdoor, TEARDROP malware, and related components. As we stated before, we suspect that NOBELIUM can draw from significant operational resources often showcased in their campaigns, including custom-built malware and tools. In March 2021, we profiled NOBELIUM’s GoldMax, GoldFinder, and Sibot malware, which it uses for layered persistence. We then followed that up with another post in May, when we analyzed the actor’s early-stage toolset comprising EnvyScout, BoomBox, NativeZone, and VaporRage.


This blog is another in-depth analysis of newly detected NOBELIUM malware: a post-exploitation backdoor that Microsoft Threat Intelligence Center (MSTIC) refers to as FoggyWeb. As mentioned in previous blogs, NOBELIUM employs multiple tactics to pursue credential theft with the objective of gaining admin-level access to Active Directory Federation Services (AD FS) servers. Once NOBELIUM obtains credentials and successfully compromises a server, the actor relies on that access to maintain persistence and deepen its infiltration using sophisticated malware and tools. NOBELIUM uses FoggyWeb to remotely exfiltrate the configuration database of compromised AD FS servers, decrypted token-signing certificate, and token-decryption certificate, as well as to download and execute additional components. Use of FoggyWeb has been observed in the wild as early as April 2021.

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