Yurei ransomware is a newly emerged, sophisticated ransomware family targeting Windows environments. It utilizes strong encryption methods, specifically ChaCha20 symmetric encryption combined with ECIES (Elliptic Curve Integrated Encryption Scheme) for key exchange, ensuring rapid and secure encryption of victim data. Files are encrypted and appended with a .Yurei extension, and the malware actively disables Windows recovery options to prevent restoration from backups or shadow copies. Propagation mechanisms include exploitation of SMB shares, infection via removable drives, and credential-based remote execution techniques, allowing lateral movement within networks. Yurei incorporates anti-forensics capabilities such as wiping event logs and securely deleting files to hinder incident response and forensic investigations. It also implements double-extortion tactics by threatening to leak stolen data if ransom demands are not met, increasing pressure on victims to pay. Analysis reveals code reuse from the Prince ransomware, suggesting a professional and mature codebase. Indicators of compromise include specific file hashes and a unique onion domain used for ransom negotiations. Although no known exploits are reported in the wild yet, the ransomware’s stealth, speed, and advanced features make it a high operational risk. The malware leverages multiple MITRE ATT&CK techniques such as T1047 (Windows Management Instrumentation), T1129 (Shared Modules), T1006 (Execution through API), and others, highlighting its complex attack chain.

For European organizations, especially those in Germany where infections have been identified, Yurei ransomware poses a significant threat to data confidentiality, integrity, and availability. The rapid encryption and disabling of recovery options can cause severe operational disruptions, data loss, and financial damage. The double-extortion component increases reputational risk and regulatory exposure under GDPR due to potential data leaks. Organizations with extensive SMB network shares or reliance on removable media are particularly vulnerable to lateral spread. The anti-forensics features complicate incident response and forensic investigations, potentially prolonging downtime and recovery efforts. Critical infrastructure, manufacturing, healthcare, and financial sectors in Europe could face heightened risks given their reliance on Windows systems and interconnected networks. The threat also raises concerns about supply chain security and insider threats due to credential-based propagation. Overall, Yurei could cause substantial economic and operational impacts if not mitigated promptly.

1. Implement strict network segmentation and limit SMB share access to only necessary users and systems, employing least privilege principles. 2. Enforce multi-factor authentication (MFA) for all remote access and credential usage to reduce risk of credential-based execution. 3. Disable or restrict use of removable drives where possible, or enforce strict scanning and control policies. 4. Deploy advanced endpoint detection and response (EDR) solutions capable of detecting the specific Yurei indicators such as file hashes and Yara rules. 5. Monitor and alert on suspicious activities including log wiping, secure deletion attempts, and unusual SMB traffic patterns. 6. Maintain offline, immutable backups and regularly test recovery procedures to ensure resilience against ransomware encryption and recovery option disabling. 7. Conduct regular user training focused on phishing and credential security to reduce initial infection vectors. 8. Apply the principle of least privilege to service accounts and disable unnecessary Windows Management Instrumentation (WMI) and remote execution capabilities. 9. Collaborate with threat intelligence sharing platforms to stay updated on Yurei developments and IoCs. 10. Prepare incident response plans specifically addressing double-extortion ransomware scenarios, including legal and communication strategies.