The ongoing multi-vendor investigations into the SolarWinds mega-hack took another twist this week with the discovery of new malware artifacts that could be used in future supply chain attacks.
According to a new report from anti-malware firm SentinelOne, the latest wave of attacks being attributed to APT29/Nobelium threat actor includes a custom downloader that is part of a “poisoned update installer” for electronic keys used by the Ukrainian government.
SentinelOne principal threat researcher Juan Andrés Guerrero-Saade documented the latest finding in a blog post that advances previous investigations from Microsoft and Volexity. “At this time, the means of distribution [for the poisoned update installer] are unknown. It’s possible that these update archives are being used as part of a regionally-specific supply chain attack,” Guerrero-Saade said.
Guerrero-Saade said the latest iteration of malware activity linked to Nobelium uses a convoluted multi-stage infection chain that runs five to six layers deep. This includes the use of ‘DLL_stageless’ downloaders, called NativeZone, that serves as booby-trapped update installer for a Ukrainian cryptographic smartkey used in government operations.
Guerrero-Saade’s analysis of the campaign found the Cobalt Strike Beacon payload serving as an “early scout” that enables selective distribution of unique payloads directly into memory. “After years of burned iterations on custom toolkits, [this APT] has opted for maximizing return on investment by simply lowering their upfront investment.”
“We stop short of referring to this as a supply chain attack since we lack visibility into its means of distribution. The poisoned installer may be delivered directly to relevant victims that rely on this regional solution. Alternatively, the attackers may have found a way of abusing an internal resource to distribute their malicious ‘update’,” Guerrero-Saade said.