What are the essential steps to recover a system from a ransomware attack when a viable backup is available?

The essential steps to recover a system from a ransomware attack when a viable backup is available are as follows. First, immediately isolate the infected system from the network. This prevents the ransomware from spreading to other devices and encrypting more data. Disconnect the network cable or disable the Wi-Fi adapter. Second, identify the type of ransomware. Knowing the specific strain of ransomware can help you understand its behavior and potentially find specific removal tools or decryption keys (though paying the ransom is generally not recommended). You can try to identify the ransomware by examining the ransom note, encrypted file extensions, or by using online ransomware identification tools. Third, ensure that the backup is clean. Verify that the backup predates the ransomware infection. If the backup contains encrypted files, it is compromised and should not be used. It's best practice to keep multiple backups with different retention periods to ensure you have a clean restore point. Fourth, reformat the infected system's storage drive. This completely erases the drive, removing the ransomware and any infected files. Reformatting ensures that the ransomware is completely eradicated. You can use the operating system's installation media or a specialized disk wiping tool to perform the reformatting. Fifth, reinstall the operating system. Use a clean and trusted source for the installation media to avoid reinfection. Follow the standard installation process for your operating system. Sixth, restore the system from the clean backup. Use the backup software or tools to restore the operating system, applications, and data from the clean backup. Ensure that you are restoring from the verified clean backup point. Seventh, update and patch the operating system and all applications. Install the latest security updates and patches to address any vulnerabilities that the ransomware may have exploited. This helps prevent future infections. Eighth, scan the restored system with antivirus and anti-malware software. Perform a full system scan to detect and remove any residual malware that may have survived the reformatting and restoration process. Ninth, review and improve security measures. Analyze how the ransomware infection occurred and implement measures to prevent future attacks. This may include strengthening firewall rules, improving email security, enhancing user awareness training, and implementing multi-factor authentication.