Today, CISA—in partnership with the Federal Bureau of Investigation (FBI) and Multi-State Information Sharing and Analysis Center (MS-ISAC)—released joint Cybersecurity Advisory, #StopRansomware: Medusa Ransomware. This advisory provides tactics, techniques, and procedures (TTPs), indicators of compromise (IOCs), and detection methods associated with known Medusa ransomware activity.

Medusa is a ransomware-as-a-service variant used to conduct ransomware attacks; as of December 2024, over 300 victims from critical infrastructure sectors have been impacted. Medusa actors use common techniques like phishing campaigns and exploiting unpatched software vulnerabilities.

Immediate actions organizations can take to mitigate Medusa ransomware activity: 

• Ensure operating systems, software, and firmware are patched and up to date.
• Segment networks to restrict lateral movement.
• Filter network traffic by preventing unknown or untrusted origins from accessing remote services.

CISA encourages network defenders to review the advisory and implement the recommended mitigations to reduce the likelihood and impact of Medusa ransomware incidents. See #StopRansomware and the #StopRansomware Guide for additional guidance on ransomware protection, detection, and response.