New MedusaLocker Ransomware Variant Deployed by Threat Actor
Summary:
Researchers at Cisco Talos have uncovered a financially motivated threat actor deploying a new MedusaLocker ransomware variant, dubbed “BabyLockerKZ.” First observed in late 2023, this variant distinguishes itself from the original MedusaLocker by using unique autorun keys and an additional public-private key set stored in the registry. Despite these differences, BabyLockerKZ utilizes the same chat and leak site URLs as its predecessor, marking its first identification as a MedusaLocker variant. The threat actor has been active since at least 2022, initially targeting organizations in Europe, with a particular focus on France, Germany, Spain, and Italy. However, since Q2 2023, the actor shifted its attention to South America, impacting countries like Brazil, Mexico, Argentina, and Colombia. This change led to a near doubling in the number of monthly victims. Before 2024, the group consistently compromised around 200 unique IP addresses each month, but activity decreased in Q1 2024.
The group employs a variety of known tools and techniques to infiltrate and move laterally within compromised networks. Many of their tools are wrappers around publicly available attack utilities but include enhanced functionality for automating and streamlining operations. Key tools observed include HRSword_v5.0.1.1.rar, used to disable antivirus and endpoint detection and response software, and Advanced_Port_Scanner_2.5.3869[.]exe, a network-scanning tool enhanced with extra features for mapping internal networks and identifying connected devices. In addition to these tools, the attackers rely on lesser-known custom tools to facilitate their attacks. One of these is an app called “Checker,” which bundles several publicly available applications into a single graphical user interface. This tool helps attackers manage stolen credentials during lateral movement across compromised networks. These tools often share a PDB path containing the phrase "paid_memes," indicating they are compiled alongside BabyLockerKZ. During attacks, the threat actor frequently stores tools in the compromised system's user folders, such as Music, Pictures, or Documents, likely to evade detection by blending in with legitimate file storage patterns.
Security Officer Comments:
The threat actor leverages "living off the land" binaries, which use native tools and scripts within the target environment to avoid detection and reduce the reliance on third-party software. This approach allows the attacker to conduct credential theft and lateral movement discreetly. By using automated tools and public utilities enhanced with additional features, the threat actor streamlines the attack process, making it easier to escalate privileges, disable security mechanisms, and deploy the ransomware payload across the network. Researchers assessed with medium confidence that the actor is financially driven and likely operates either as an initial access broker or as an affiliate of a larger ransomware cartel. The group’s operational tactics suggest a role in facilitating broader ransomware campaigns by gaining initial access to targeted networks and selling that access to other threat actors.
Suggested Corrections:
IOCs:
https://blog.talosintelligence.com/...preading-new-medusalocker-variant-since-2022/
Backup your data, system images, and configurations, regularly test them, and keep the backups offline: Ensure that backups are regularly tested and that they are not connected to the business network, as many ransomware variants try to find and encrypt or delete accessible backups. Maintaining current backups offline is critical because if your network data is encrypted with ransomware, your organization can restore systems.
Update and patch systems promptly: This includes maintaining the security of operating systems, applications, and firmware in a timely manner. Consider using a centralized patch management system; use a risk-based assessment strategy to drive your patch management program.
Test your incident response plan: There's nothing that shows the gaps in plans more than testing them. Run through some core questions and use those to build an incident response plan: Are you able to sustain business operations without access to certain systems? For how long? Would you turn off your manufacturing operations if business systems such as billing were offline?
Check Your Security Team's Work: Use a 3rd party pen tester to test the security of your systems and your ability to defend against a sophisticated attack. Many ransomware criminals are aggressive and sophisticated and will find the equivalent of unlocked doors.
Segment your networks: There's been a recent shift in ransomware attacks – from stealing data to disrupting operations. It's critically important that your corporate business functions and manufacturing/production operations are separated and that you carefully filter and limit internet access to operational networks, identify links between these networks and develop workarounds or manual controls to ensure ICS networks can be isolated and continue operating if your corporate network is compromised. Regularly test contingency plans such as manual controls so that safety critical functions can be maintained during a cyber incident.
Train employees: Email remains the most vulnerable attack vector for organizations. Users should be trained how to avoid and spot phishing emails. Multi Factor authentication can help prevent malicious access to sensitive services.
Link(s):
https://www.infosecurity-magazine.com/news/medusalocker-ransomware-deployed/
https://blog.talosintelligence.com/...preading-new-medusalocker-variant-since-2022/
Researchers at Cisco Talos have uncovered a financially motivated threat actor deploying a new MedusaLocker ransomware variant, dubbed “BabyLockerKZ.” First observed in late 2023, this variant distinguishes itself from the original MedusaLocker by using unique autorun keys and an additional public-private key set stored in the registry. Despite these differences, BabyLockerKZ utilizes the same chat and leak site URLs as its predecessor, marking its first identification as a MedusaLocker variant. The threat actor has been active since at least 2022, initially targeting organizations in Europe, with a particular focus on France, Germany, Spain, and Italy. However, since Q2 2023, the actor shifted its attention to South America, impacting countries like Brazil, Mexico, Argentina, and Colombia. This change led to a near doubling in the number of monthly victims. Before 2024, the group consistently compromised around 200 unique IP addresses each month, but activity decreased in Q1 2024.
The group employs a variety of known tools and techniques to infiltrate and move laterally within compromised networks. Many of their tools are wrappers around publicly available attack utilities but include enhanced functionality for automating and streamlining operations. Key tools observed include HRSword_v5.0.1.1.rar, used to disable antivirus and endpoint detection and response software, and Advanced_Port_Scanner_2.5.3869[.]exe, a network-scanning tool enhanced with extra features for mapping internal networks and identifying connected devices. In addition to these tools, the attackers rely on lesser-known custom tools to facilitate their attacks. One of these is an app called “Checker,” which bundles several publicly available applications into a single graphical user interface. This tool helps attackers manage stolen credentials during lateral movement across compromised networks. These tools often share a PDB path containing the phrase "paid_memes," indicating they are compiled alongside BabyLockerKZ. During attacks, the threat actor frequently stores tools in the compromised system's user folders, such as Music, Pictures, or Documents, likely to evade detection by blending in with legitimate file storage patterns.
Security Officer Comments:
The threat actor leverages "living off the land" binaries, which use native tools and scripts within the target environment to avoid detection and reduce the reliance on third-party software. This approach allows the attacker to conduct credential theft and lateral movement discreetly. By using automated tools and public utilities enhanced with additional features, the threat actor streamlines the attack process, making it easier to escalate privileges, disable security mechanisms, and deploy the ransomware payload across the network. Researchers assessed with medium confidence that the actor is financially driven and likely operates either as an initial access broker or as an affiliate of a larger ransomware cartel. The group’s operational tactics suggest a role in facilitating broader ransomware campaigns by gaining initial access to targeted networks and selling that access to other threat actors.
Suggested Corrections:
IOCs:
https://blog.talosintelligence.com/...preading-new-medusalocker-variant-since-2022/
Backup your data, system images, and configurations, regularly test them, and keep the backups offline: Ensure that backups are regularly tested and that they are not connected to the business network, as many ransomware variants try to find and encrypt or delete accessible backups. Maintaining current backups offline is critical because if your network data is encrypted with ransomware, your organization can restore systems.
Update and patch systems promptly: This includes maintaining the security of operating systems, applications, and firmware in a timely manner. Consider using a centralized patch management system; use a risk-based assessment strategy to drive your patch management program.
Test your incident response plan: There's nothing that shows the gaps in plans more than testing them. Run through some core questions and use those to build an incident response plan: Are you able to sustain business operations without access to certain systems? For how long? Would you turn off your manufacturing operations if business systems such as billing were offline?
Check Your Security Team's Work: Use a 3rd party pen tester to test the security of your systems and your ability to defend against a sophisticated attack. Many ransomware criminals are aggressive and sophisticated and will find the equivalent of unlocked doors.
Segment your networks: There's been a recent shift in ransomware attacks – from stealing data to disrupting operations. It's critically important that your corporate business functions and manufacturing/production operations are separated and that you carefully filter and limit internet access to operational networks, identify links between these networks and develop workarounds or manual controls to ensure ICS networks can be isolated and continue operating if your corporate network is compromised. Regularly test contingency plans such as manual controls so that safety critical functions can be maintained during a cyber incident.
Train employees: Email remains the most vulnerable attack vector for organizations. Users should be trained how to avoid and spot phishing emails. Multi Factor authentication can help prevent malicious access to sensitive services.
Link(s):
https://www.infosecurity-magazine.com/news/medusalocker-ransomware-deployed/
https://blog.talosintelligence.com/...preading-new-medusalocker-variant-since-2022/