November 27, 2022
The highly active Black Basta ransomware has been linked by cybersecurity firm Sentinel One to the notorious Russian cybercrime group known as FIN7. Initially spotted in April 2022, Black Basta became a prevalent threat within the first two months of operation, and is estimated to have breached over 90 organizations by September 2022. Analysis of…

The highly active Black Basta ransomware has been linked by cybersecurity firm Sentinel One to the notorious Russian cybercrime group known as FIN7.

Initially spotted in April 2022, Black Basta became a prevalent threat within the first two months of operation, and is estimated to have breached over 90 organizations by September 2022.

Analysis of the ransomware operation has revealed a well-organized and well-resourced operator that does not attempt to recruit affiliates, indicating that the threat actor is developing their toolkit in-house and might be collaborating with a small number of affiliates.

Sentinel One says that its investigation into Black Basta has also surfaced the use of multiple tools created by one or more FIN7 (aka Carbanak) developers, suggesting a tight connection with the cybercrime group.

Black Basta infections observed in June involved spam emails containing macro-enabled Office documents designed to drop Qakbot for persistence.

The backdoor allows the attackers to perform system reconnaissance using several tools that are executed manually, including the SharpHound and BloodHound frameworks, which allow for Active Directory enumeration via LDAP queries, and the SoftPerfect network scanner.

Next, the Black Basta operators attempt to exploit multiple known vulnerabilities to elevate their privileges, including NoPac (CVE-2021-42287, CVE-2021-42278) PrintNightmare (CVE-2021-34527), and ZeroLogon (CVE-2020-1472).

Sentinel One has observed the ransomware operators using various remote access tools (RATs) and relying on batch scripts for lateral movement.

The malware operators deploy and execute additional batch scripts that allow them to cripple or completely disable security solutions, including a custom defense impairment tool that was used exclusively in some Black Basta attacks.

An analysis of this custom tool led to the discovery of a custom-packed Birddog sample – also known as SocksBot, this backdoor is known to be part of the FIN7 arsenal – that helped Sentinel One link the impairment tool and the custom packer to the same developer.

Sentinel One was able to link Black Basta to FIN7 via multiple code artifacts in different tools used in ransomware attacks, the use of a custom packer, the use of FIN7-attributed PowerShell scripts, and infrastructure overlaps.

“We assess it is highly likely the BlackBasta ransomware operation has ties with FIN7. Furthermore, we assess it is likely that the developer(s) behind their tools to impair victim defenses is, or was, a developer for FIN7,” Sentinel One says.

Related: Black Basta Ransomware Becomes Major Threat in Two Months

Related: FIN7 Cybercrime Operation Continues to Evolve Despite Arrests

Related: BlackByte Ransomware Abuses Legitimate Driver to Disable Security Protections

Ionut Arghire is an international correspondent for SecurityWeek. Previous Columns by Ionut Arghire:Tags:
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