Plesk comes with a lot of pre-installed and available features for security. A version of Plesk has enhanced security as well as pre-installed advisor extension. For added security, we would suggest the following
Set up the password with minimum strength
Use Google Authenticator extension available inside Plesk
Secure Plesk web hosting control panel via SSL/TLS certificates
Use secure FTP connects over FTP connections
Use the security check feature in the WordPress toolkit for WordPress installations
Don’t use out-dated applications
Use Fail2Ban for safety against hack attempts
Non-standard port for SSH