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Ransomware Spotlight: Black Basta




 Black Basta

By Trend Micro Research

A relative newcomer in 2022, the Black Basta ransomware group has wasted no time making a name for itself by upgrading its toolset and racking up its victim count around the world mere months since its ransomware was first detected. Learn more about this new ransomware and fortify your organization’s defenses against this threat. 

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Black Basta is a ransomware group operating as ransomware-as-a-service (RaaS) that was initially spotted in April 2022. It has since proven itself to be a formidable threat, as evidenced by its use of double-extortion tactics and expansion of its attack arsenal to include tools like the Qakbot trojan and PrintNightmare exploit.

Detections of the Black Basta ransomware are currently low, likely because of how recently it was discovered. And like most modern ransomware, Black Basta has a more targeted approach to choosing its victims rather than relying on spray-and-pray tactics. However, the speed with which its malware authors have augmented their attack arsenal and developed a new Linux build merits further investigation of the emerging ransomware gang behind it.

What organizations need to know about Black Basta


The Black Basta ransomware group quickly gained notoriety after it laid claim to massive breaches earlier this year. On April 20, 2022, a user under the name “Black Basta” sought out corporate network access credentials on underground forums in exchange for a share of the profits from their ransomware attacks. Specifically, the user was in the market for credentials that could compromise organizations based in English-speaking countries, including Australia, Canada, New Zealand, the UK, and the US.

Two days later, the American Dental Association (ADA) suffered a cyberattack that led it to shutter multiple systems. Data allegedly stolen from the ADA was published on the Black Basta leak site only 96 hours after the attack.

While it was previously assumed that the ransomware group used bought or stolen corporate network access credentials to infiltrate its victims’ networks, our analysis of another set of samples monitored within a 72-hour time frame shows a possible correlation between the Qakbot trojan and the Black Basta ransomware. Black Basta continued to evolve, and in June, a Linux build of the ransomware that encrypts VMware ESXi virtual machines was discovered in the wild.

Interestingly, the ransomware group does not appear to distribute its malware at random. That Black Basta’s operators have turned to underground markets to acquire network access credentials and have hard-coded a unique ID in every Black Basta build betrays their mature understanding of how ransomware works as a business. While Black Basta may be a newly formed group, the individuals behind it are likely seasoned cybercriminals.

Top affected countries and industries according to Trend Micro data

In this section, we discuss Trend Micro™ Smart Protection Network™ data on Black Basta’s activity from April 1 to July 31, 2022, which refers to detections of the ransomware’s attempts to compromise organizations.

Just two countries accounted for over half of the group’s 44 ransomware attack attempts during this period, which were concentrated in the US at 43%, with Austria a distant second at 15%. As Black Basta has sought to purchase network access credentials for organizations located specifically in the US, among other countries, this may explain the higher number of attacks against US-based businesses.

The countries with the most Black Basta ransomware attack attempts in terms of infected machines from April 1 to July 31, 2022

Figure 1. The countries with the most Black Basta ransomware attack attempts in terms of infected machines from April 1 to July 31, 2022
Source: Trend Micro™ Smart Protection Network™

As of this writing, our detections show that Black Basta activity is spread across many different industries. The group has been observed targeting businesses involved in technology, insurance, manufacturing, and utilities.

Although Black Basta is a relatively new arrival to the ransomware scene, its detections have been on a steady climb since the ransomware gang surfaced in April, peaking at 22 attack attempts in June before tapering down to 11 the following month.

 The numbers of detections of Black Basta ransomware attack attempts in terms of infected machines in each month from April 1 to July 31, 2022

Figure 2. The numbers of detections of Black Basta ransomware attack attempts in terms of infected machines in each month from April 1 to July 31, 2022
Source: Trend Micro Smart Protection Network

Targeted regions and industries according to Black Basta’s leak site

In this section, we look into the attacks recorded on the Black Basta group’s leak site, which represent successfully compromised organizations that, as of this writing, have refused to pay ransom. Our detections, which pertain to Trend Micro customers, captured only a fraction of the victims found in Black Basta’s leak site. Trend Micro’s open-source intelligence (OSINT) research and investigation of the site show that from April 1 to July 31, 2022, the group compromised a total of 80 organizations.

The bulk of Black Basta’ victims were based in North America, which had a victim count of 44, followed by Europe and the Asia-Pacific. More specifically, the US was at the receiving end of most of the attacks, with 38 affected organizations. Many confirmed ransomware attacks also took place in Germany, with 19 victims.

The distribution by region of Black Basta’s victim organizations from April 1 to July 31, 2022

Figure 3. The distribution by region of Black Basta’s victim organizations from April 1 to July 31, 2022
Sources: Black Basta’s leak site and Trend Micro’s OSINT research

The distribution by country of Black Basta’s victim organizations from April 1 to July 31, 2022

Figure 4. The distribution by country of Black Basta’s victim organizations from April 1 to July 31, 2022
Sources: Black Basta’s leak site and Trend Micro’s OSINT research

. . .

Black Basta’s attacks affected a variety of organizations. Construction businesses topped the list with a victim count of 10, while businesses involved in professional services came in second with nine victims. Medium-size organizations made up the lion’s share of recorded Black Basta victims.

The distribution by industry of Black Basta’s victim organizations from April 1 to July 31, 2022

Figure 5. The distribution by industry of Black Basta’s victim organizations from April 1 to July 31, 2022
Sources: Black Basta’s leak site and Trend Micro’s OSINT research

The distribution by organization size of Black Basta’s victim organizations from April 1 to July 31, 2022

Figure 6. The distribution by organization size of Black Basta’s victim organizations from April 1 to July 31, 2022
Sources: Black Basta’s leak site and Trend Micro’s OSINT research

Infection chain and techniques

As Black Basta’s operations are based on the RaaS model, its infection chain might vary depending on the target. The infection chain illustrated below details the variety of tactics and tools the group uses.

Black Basta’s infection chain

Figure 7. Black Basta’s infection chain


Initial access

  • External data reports that a user named “Black Basta” posted on underground forums seeking corporate network access credentials, offering a share of the profit from their attacks as payment. These reports are supported by the fact that a unique ID is hard-coded in each Black Basta build, which could also mean that the ransomware gang does not distribute its malware sporadically.
  • Our internal telemetry shows another set of samples, which were monitored within a 72-hour time frame, that were using Qakbot. The malware is downloaded and executed from a malicious Excel file and then executes certain PowerShell commands as part of its staging phase

Discovery

  • Black Basta uses PowerShell scripts to scan information about the compromised system or network.
  • It uses Qakbot’s and Cobeacon’s information-gathering capabilities to scan the compromised system or network.
  • It uses third-party tools such as Netcat to scan the compromised system or network.

Defense evasion

  • Black Basta uses a batch script containing PowerShell commands to disable antimalware applications.
  • It uses Group Policy Objects (GPOs) to disable Windows Defender and Security Center.
  • It reboots the victim’s computer in safe mode to circumvent any antimalware applications.

Privilege escalation


Credential access

  • Black Basta uses Mimikatz to dump credentials.

Lateral movement

  • Black Basta uses different tools and pieces of malware to spread its ransomware to other remote systems in the network:
    • BITSAdmin
    • PsExec 
    • Windows Management Instrumentation (WMI)
    • RDP 
    • Qakbot 
    • Cobeacon 

Exfiltration

  • Black Basta uses Cobeacon to exfiltrate the stolen data on an established command-and-control (C&C) server.
  • It uses Rclone to exfiltrate data from compromised systems.

Impact

  • Black Basta uses the ChaCha20 algorithm to encrypt files. The ChaCha20 encryption key is then encrypted with a public RSA-4096 key that is included in the executable.
  • Multiple builds of Black Basta ransomware have been found in the wild
    • One build restarts the victim’s system in safe mode, most likely for evasion purposes, before performing encryption. This build also modifies the “Fax” service to enable it to run in safe mode and with service-level access.
    • Another build contains only the ransomware’s core capabilities, such as wallpaper defacement, file encryption, and deletion of shadow copies.
    • A newly found build has a new addition: the -bomb argument, which theoretically allows the ransomware to automatically target all connected machines for encryption.
    • The Linux build of the ransomware targets the folder /vmfs/volumes, where images from virtual machines are contained, for encryption. To encrypt other folders, the ransomware actors include the -forcepath argument.
  • Black Basta displays a ransomware note as the victim’s wallpaper directing them to a .txt file with more details.
    Black Basta displays a ransomware note as the victim’s wallpaper directing them to a .txt file with more details

Other technical details

  • Black Basta avoids encrypting files in these folders:
    • $Recycle.Bin
    • Windows
    • Local Settings
    • Application Data
    • boot
  • It avoids encrypting files with these strings in their file names:
    • OUT.txt
    • NTUSER.DAT
    • readme.txt (the ransom note)
    • dlaksjdoiwq.jpg (a desktop wallpaper found in the %TEMP% folder)
    • fkdjsadasd.ico (an icon used for encrypted files, found in the %TEMP% folder)
  • It drops a ransom note as a .txt file in an encrypted folder in the victim’s machine.

    Figure 9. An example of the contents of the ransom note .txt file

MITRE ATT&CK tactics and techniques

Initial accessExecutionPrivilege escalationDefense evasionCredential accessDiscoveryLateral movementExfiltrationImpact

T1078 - Valid accounts
Has been reported buying compromised accounts on underground forums to access victim systems.

T1566.001 - Phishing: Spear-phishing attachment
Mirrors technique used by Qakbot operators to distribute their payload that will deliver the ransomware.

T1059.003 - Command and scripting interpreter
Uses various scripting interpreters like PowerShell and Windows command shell.

T1569.002 - System services: Service execution
Stops and deletes the service named “Fax”, which it then impersonates for its encryption routine.

T1047 - Windows Management Instrumentation
Has been observed to use Windows Management Instrumentation (WMI) to spread and execute files over the Network.

T1068 - Exploitation for privilege escalation
Exploits the PrintNightmare vulnerability (CVE-2021-34527) to perform privileged operations

T1112 - Modify registry
Modifies registry entries to enable it to replace the desktop wallpaper, set the icon associated with encrypted files, establish persistence, and disable defenses.

T1484.001 - Domain policy modification: Group policy modification
Employs a technique involving the creation of a Group Policy Object (GPO) on a compromised domain controller, which will push out the changes (disable defenses) to the Windows registry of domain-joined hosts.

T1562.001 - Impair defenses: Disable or modify tools
Disables Windows Defender and Security Center.

T1562.009 - Impair defenses: Safe mode boot
Disables Windows recovery and repair features and restarts the machine in safe mode.

T1620 - Reflective code loading
Has some builds that are known to use reflective code loading when executing themselves.

T1003 - OS credential dumping
Uses Mimikatz to dump credentials.

T1082 - System information discovery
Uses tools for local system scans.

T1018 - Remote system discovery
Uses tools for remote network scans.

T1083 - File and directory discovery
Searches for specific files and directories related to its ransomware encryption.

T1570 - Lateral tool transfer
Uses tools like PsExec and BITSAdmin to spread the malware laterally across the network.

T1021.001 - Remote services: Remote Desktop Protocol
Uses RDP to spread and execute the malware across the network.

T1041 - Exfiltration over C&C channel
Uses an established command-and-control (C&C) channel to exfiltrate data.

T1567 - Exfiltration over web service
Uses a tool like Rclone to copy stolen data from a client to its cloud server.

T1490 - Inhibit system recovery
Deletes shadow copies.

T1489 - Service stop
Stops and deletes a service named “Fax”, which it then impersonates for its encryption routine.

T1486 - Data encrypted for impact
Encrypts files and adds the extension “.basta”.

T1491 - Defacement
Replaces the desktop wallpaper to display the ransom note.

Summary of tools, exploit, and other malware used

Security teams can keep an eye out for the presence of these tools, exploit, and other malware that are typically used in Black Basta’s ransomware attacks:

Initial accessDiscoveryPrivilege escalationCredential accessLateral movementExecutionExfiltrationCommand and controlImpact
  • Spear phishing
  • Netcat
  • PrintNightmare vulnerability (CVE-2021-34527)
  • Mimikatz
  • BITSAdmin
  • Coroxy
  • PsExec
  • RDP
  • WMI
  • PowerShell
  • Windows command shell
  • WMI
  • Cobeacon
  • Rclone
  • Cobeacon
  • Qakbot(Qbot)
  • Black Basta ransomware

Security recommendations

Security researchers have speculated that Black Basta might be an offshoot of the infamous Conti ransomware gang. It has also exhibited similarities to the Black Matter ransomware gang, including a resemblance between their respective leak sites. Its possible connection to these ransomware groups might explain the high level of in-house expertise behind Black Basta’s attacks.

In defending systems against threats like Black Basta, organizations can benefit from establishing security frameworks that can allocate resources systematically for establishing solid defenses against ransomware. Here are some best practices that can be included in these frameworks:


Audit and inventory

  • Take an inventory of assets and data.
  • Identify authorized and unauthorized devices and software.
  • Make an audit of event and incident logs.

Configure and monitor

  • Manage hardware and software configurations.
  • Grant admin privileges and access only when necessary to an employee’s role.
  • Monitor network ports, protocols, and services.
  • Activate security configurations on network infrastructure devices such as firewalls and routers.
  • Establish a software allowlist that only executes legitimate applications.

Patch and update

  • Conduct regular vulnerability assessments.
  • Perform patching or virtual patching for operating systems and applications.
  • Update software and applications to their latest versions.

Protect and recover

  • Implement data protection, backup, and recovery measures.
  • Enable multifactor authentication (MFA).

Secure and defend

  • Employ sandbox analysis to block malicious emails.
  • Deploy the latest versions of security solutions to all layers of the system, including email, endpoint, web, and network.
  • Detect early signs of an attack such as the presence of suspicious tools in the system.
  • Use advanced detection technologies such as those powered by AI and machine learning.

Train and test

  • Regularly train and assess employees on security skills.
  • Conduct red-team exercises and penetration tests.

A multilayered approach can help organizations guard possible entry points into the system (endpoint, email, web, and network). Security solutions that can detect malicious components and suspicious behavior can also help protect enterprises:

  • Trend Micro Vision One™ provides multilayered protection and behavior detection, which helps block questionable behavior and tools early on before the ransomware can do irreversible damage to the system.
  • Trend Micro Cloud One™ – Workload Security protects systems against both known and unknown threats that exploit vulnerabilities. This protection is made possible through techniques such as virtual patching and machine learning.
  • Trend Micro™ Deep Discovery™ Email Inspector employs custom sandboxing and advanced analysis techniques to effectively block malicious emails, including phishing emails that can serve as entry points for ransomware.
  • Trend Micro Apex One™ offers next-level automated threat detection and response against advanced concerns such as fileless threats and ransomware, ensuring the protection of endpoints.

Indicators of compromise (IOCs)

The indicators of compromise (IOCs) for the threat discussed in this article can be found here. Actual indicators might vary per attack.

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