Plesk is the more secure than Linux cpanel. It is more simplified than cpanel to use Plesk. Despite of many reasons many hosting companies do not offer plesk panel for hosting management. You can carry out following steps to secure your Plesk panel on Linux server:
1. Allow SSH access via a keyfile.
2. Use a non-standard port for SSH connections.
3. Forbid the SSH authentication for root.
4. Switch off Perl and Python if it is not required for the website and never use mod_perl and mod_python.
5. Install Opsani VCTR to scan for vulnerabilities.
6. Install Fail2Ban to block hack attempts.
7. Do not use PHP handler served as Apache module since it is not secure.
8. Enable automatic updates for the system packages.