Two Threat Actors, One Targeted Threat

When the GrandCrab ransomware operators quit the arena, they left an vacuum that others have tried to fill.

Since April 2019, Sodinokibi (a.k.a. REvil) has been a major player. The operation has gained the respect of fellow cybercriminals as well as security researchers.

The ransomware, for example, has been deployed on Oracle WebLogic servers through the use of a critical deserialization vulnerability. \r\nThere is an interesting similarity between the GrandCrab ransomware and REvil's malware in one area. Both will not do business in Russia, Ukraine, Moldova, Belarus, Kyrgyzstan, Kazakhstan, Armenia, Tajikistan, Turkmenistan or Uzbekistan.

REvil had the malware, but not the reach to deliver it as widely as they would have wished.

AdvIntel, a NYC-based security firm with some seemingly deep contacts in Russia, says it noticed a threat actor with a moniker of -TMT- joining a top-level Russian hack forum in May of this year.

He then started talking about his "warez." AdvIntel further observed that during, "June, July, and August, they were looking for customers to monetize corporate network compromises, however, not specifying the victim names, instead referring to the breaches as 'fat accesses'. At the same time, in private communication, -TMT- offered several accesses to compromised entities, as well as stolen credentials for administrative accounts on the victim's websites. Their breach prices ranged from $3,000 to $5,000 USD."

They said they had the access. They said they had a way to do this that seemed reasonable. Their Tactics, Techniques & Procedures (TTPs) were focused on doing breaches of corporate networks. For these purposes, they were using compromised remote desktop protocols and credential-stealing malware as the initial attack vectors.

The actor even said, according to AdvIntel, that Cobalt Strike Beacon was used to access secure environments. Beacon is Cobalt Strike's payload used for as initial payload. Beacon's shell command allows executing command prompt commands on the compromised host.

REvil noticed. Since August 2019, AdvIntel says, -TMT- had been partnering with REvil developers to support the -TMT- crypto locker uploads. Both parties joined in an effort to customize ransomware admin panels so that they didn't need to be rented from a third-party as a service. It was also expressed by the hacker forum participants that an approach with less third-party participation added to the security of a overall ransomware operation.

They also think that the joining of -TMT- and REvil was the main reason why the two actors almost simultaneously left the Exploit forum, no doubt to communicate by other means with each other. AdvIntel also said in the blog that, "The data breach community has been constantly sharing their concerns regarding the inefficiency of direct breach monetization via underground forums. Indeed, many high-profile breaches were compromised by unexperienced buyers or law enforcement during the initial examination of the admin panel access."

So, it seems that publicly hanging out your accesses for sale in an access-as-a-service scheme wasn't a great business model. But by combining, the two threat actors leveraged their own specific areas of expertise into one highly efficient -- and private -- tool.

— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.