Mitigating Ransomware Risks in Mid-Sized Tech-Driven Companies

The “#StopRansomware: Black Basta” document, published by CISA on May 10, 2024, is a concise overview of key cybersecurity practices recommended for protecting mid-sized companies with technology departments against ransomware attacks, specifically targeting the Black Basta ransomware variant. Insights are drawn from a collaborative cybersecurity advisory involving the FBI, CISA, HHS, and MS-ISAC. 

Black Basta, a ransomware-as-a-service (RaaS), uses spearphishing and exploits known vulnerabilities for initial access. After entry, it deploys a double-extortion tactic by encrypting data and threatening to publish it unless a ransom is paid. Key techniques include: 

  • Initial Access: Spearphishing and exploiting vulnerabilities  
  • Privilege Escalation: Using tools like Mimikatz and exploiting vulnerabilities like ZeroLogon and PrintNightmare. 
  • Lateral Movement: Utilizing BITSAdmin, PsExec, and remote desktop protocols. 
  • Exfiltration and Encryption: Using RClone for data exfiltration and ChaCha20 for encryption. 

IOCs include specific hashes of malicious files (e.g., RClone and WinSCP executables) and network indicators tied to Black Basta’s operations. 

Effective mitigation strategies include: 

  • Patch Management: Prompt installation of updates for all software and firmware, prioritizing Known Exploited Vulnerabilities (KEV). 
  • Phishing-Resistant Multi-Factor Authentication (MFA): Extensive implementation across systems, especially for services allowing remote access. 
  • Back-Up and Recovery: Regular backups of critical data and system configurations to facilitate recovery from attacks. 
  • Vulnerability Management: Regular assessments and prioritization of vulnerabilities based on potential impact and exploitability. 

Tools that should be in place for robust cybersecurity include: 

  • Endpoint Detection and Response (EDR) tools: To monitor and respond to threats. 
  • Security Information and Event Management (SIEM): For real-time analysis and logging of security alerts. 
  • Automated Patch Management Systems: To ensure timely application of security patches.