The security firms Malwarebytes and HYAS have strung together several pieces of evidence that they believe tie Magecart Group 4 to the Cobalt Group.

The two companies found that the Cobalt Group and Magecart Group 4 have several overarching similarities, such as the use of advanced techniques during their attacks and a history with banking malware. Additionally, the research firms found some underlying stylistic parallels that serve as circumstantial evidence that the two are the same entity.

Malwarebytes found connections between email registrants and exfiltration gates. For example, the client-side and server-side skimmer domains bootstraproxy[.]com and s3-us-west[.]com are registered to [email protected] and are listed by RiskIQ as being used by Magecart Group 4 in its report Group 4: Never gone, simply advancing IOCS.

“By checking their exfiltration gates (secure.upgradenstore[.]com and secureqbrowser[.]com), we connected them to other registrant emails and saw a pattern emerge. Email addresses used to register Magecart domains belonging to Magecart Group 4 contain a [first name], [initial], and [last name],” Malwarebytes said.

Perhaps the key to tying the groups together lies with the emails found associated with Magecart attacks and that have been used historically by Cobalt. The vast majority of the Magecart Group 4 emails use protonmail accounts with a sprinkling of tutanota/ accounts, which are also favored by Cobalt. Additionally, the Magecart email configurations are [first name], [initial], and [last name] with Cobalt using [first name], [last name].

“Given the use of privacy services for all the domains in question, it is highly unlikely that this naming convention would be known to any other actor besides those who registered both the Cobalt Group and Magecart infrastructure. In addition, further investigation revealed that regardless of the email provider used, 10 of the seemingly separate accounts reused only two different IP addresses, even over weeks and months between registrations,” Malwarebytes noted.

For the final piece of the puzzle, Malwarebytes considered the fact that other cybergangs in the same class as Cobalt Group, such as Fin6, have entered the Magecart space, so it is only logical that Cobalt would do so as well in order to diversity its criminal portfolio.

Cobalt, which has been operating since 2013 and is credited with hitting more than 100 banks, has had a tough couple of years, with its leader having been arrested in Spain in March 2018. But the gang bounced back and was spotted by GroupIB the following May sending phishing emails to Russian financial institutions.