The Analytic->Alerts page allows you to enable ransomware detection and configures that action upon such detection.

Enable the Ransomware Detection option to setup alerts when one of the thousands of ransomware file extensions is detected. Morro Data maintains a list of known ransomware file extensions and this list is by no means complete and may not be up-to-date.  Other than receiving email alerts, the admin can optionally shuts down all CacheDrives immediately upon detection of such file extensions.