Behavior:Win32/BlackCat.MK

Guidance for individual users

For more tips on how to keep your device safe,

• Go to the Microsoft security help & learning portal.
• Go to aka.ms/ransomwaresolutions for general information and frequently asked questions about ransomware, defense against ransomware, and ransomware incident response playbook.
• To learn more about preventing trojans or other malware from affecting individual devices, read about preventing malware infection.

Guidance for enterprise administrators and Microsoft 365 Defender customers

Ransomware more often attacks enterprises than individuals. Following the below mitigation steps can help prevent ransomware attacks:

• Keep backups so you can recover data affected by ransomware and destructive attacks. Use controlled folder access to prevent unauthorized applications from modifying protected files.
• Harden internet-facing assets and ensure they have the latest security updates. Use threat and vulnerability management to audit these assets regularly for vulnerabilities, misconfigurations, and suspicious activity.
• Monitor for brute-force attempts. Check excessive failed authentication attempts (Windows security event ID 4625).
• Turn on cloud-delivered protection and automatic sample submission on Microsoft Defender Antivirus. These capabilities use artificial intelligence and machine learning to quickly identify and stop new and unknown threats.
• Turn on the following attack surface reduction rules to block or audit associated ransomware and human adversary activities. To assess the impact of these rules, deploy them in audit mode.
• Block process creations originating from PsExec and WMI commands
• Use advanced protection against ransomware
• Block credential stealing from the Windows local security authority subsystem (lsass.exe)
• Utilize the Microsoft Defender Firewall and your network firewall to prevent RPC and SMB communication among endpoints whenever possible. This limits lateral movement as well as other attack activities.
• Turn on tamper protection features to prevent attackers from stopping security services.
• Educate end users about protecting personal and business information in social media, filtering unsolicited communication, identifying lures in spear-phishing email and watering holes, and reporting of reconnaissance attempts and other suspicious activity.