North Korean Lazarus Group Linked to Medusa Ransomware Attacks
Summary:
North Korean state-backed hackers linked to the Lazarus Group are targeting U.S. healthcare organizations in extortion attacks using the Medusa ransomware, according to a new report from Symantec.
Medusa ransomware has been active since 2021 and operates under a ransomware-as-a-service model run by the Spearwing cybercrime group, enabling affiliates to carry out attacks in exchange for a share of ransom payments.
According to Symantec, a Lazarus sub-group, likely Andariel (also known as Stonefly), is now leveraging Medusa in financially motivated intrusions, marking the first time this threat actor has been publicly associated with the operation. Alongside Medusa ransomware, the actor is using a range of tools, including:
Security Officer Comments:
While North Korean threat actors have previously been linked to multiple ransomware families, including HolyGhost, PLAY, Maui, and Qilin, Symantec notes that this is the first confirmed association with Medusa. Recent victim listings show that Medusa has targeted multiple healthcare and non-profit organizations in the United States, including an educational facility for autistic children, though not all incidents can be confidently attributed to Lazarus due to the shared affiliate model. The average ransom demand observed in these attacks is approximately $260,000, with some demands reaching significantly higher figures. Symantec adds that stolen funds are used to support espionage operations targeting defense, technology, and government entities in the United States, Taiwan, and South Korea, reinforcing that North Korean operators continue to blend cybercrime and state-directed intelligence activity, and that no sector, including healthcare, appears to be off-limits.
Suggested Corrections:
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 on how to avoid and spot phishing emails.
Implement multi-factor authentication (MFA): External-facing assets that leverage single-factor authentication (SFA) are highly susceptible to brute-forcing attacks, password spraying, or unauthorized remote access using valid (stolen) credentials. Implementing MFA enhances security and adds an extra layer of protection.
Link(s):
https://www.bleepingcomputer.com/ne...us-group-linked-to-medusa-ransomware-attacks/
North Korean state-backed hackers linked to the Lazarus Group are targeting U.S. healthcare organizations in extortion attacks using the Medusa ransomware, according to a new report from Symantec.
Medusa ransomware has been active since 2021 and operates under a ransomware-as-a-service model run by the Spearwing cybercrime group, enabling affiliates to carry out attacks in exchange for a share of ransom payments.
According to Symantec, a Lazarus sub-group, likely Andariel (also known as Stonefly), is now leveraging Medusa in financially motivated intrusions, marking the first time this threat actor has been publicly associated with the operation. Alongside Medusa ransomware, the actor is using a range of tools, including:
- Comebacker: A custom backdoor and loader exclusively associated with Lazarus.
- Blindingcan: A remote access Trojan (RAT) associated with Lazarus.
- ChromeStealer: A tool for extracting stored passwords from the Chrome browser.
- Curl: An open-source command-line tool for transferring data using various network protocols.
- Infohook: Information-stealing malware.
- Mimikatz: A publicly available credential dumping tool.
- RP_Proxy: A custom proxying tool.
Security Officer Comments:
While North Korean threat actors have previously been linked to multiple ransomware families, including HolyGhost, PLAY, Maui, and Qilin, Symantec notes that this is the first confirmed association with Medusa. Recent victim listings show that Medusa has targeted multiple healthcare and non-profit organizations in the United States, including an educational facility for autistic children, though not all incidents can be confidently attributed to Lazarus due to the shared affiliate model. The average ransom demand observed in these attacks is approximately $260,000, with some demands reaching significantly higher figures. Symantec adds that stolen funds are used to support espionage operations targeting defense, technology, and government entities in the United States, Taiwan, and South Korea, reinforcing that North Korean operators continue to blend cybercrime and state-directed intelligence activity, and that no sector, including healthcare, appears to be off-limits.
Suggested Corrections:
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 on how to avoid and spot phishing emails.
Implement multi-factor authentication (MFA): External-facing assets that leverage single-factor authentication (SFA) are highly susceptible to brute-forcing attacks, password spraying, or unauthorized remote access using valid (stolen) credentials. Implementing MFA enhances security and adds an extra layer of protection.
Link(s):
https://www.bleepingcomputer.com/ne...us-group-linked-to-medusa-ransomware-attacks/