For security reasons, you should always install a firewall to your control panel, if one is not already included. Here's our two favorites:
ConfigServer Security & Firewall (CSF) - It's free and probably the most popular one available! It’s also easy to install, just view the install.txt near the bottom of the page and use SSH to install it.
https://configserver.com/cp/csf.html
Advanced Policy Firewall (APF) - Also free and very good!
https://www.rfxn.com/projects/advanced-policy-firewall/
How To Configure Your Firewall For WHM/cPanel Services:
https://documentation.cpanel.net/display/CKB/How+to+Configure+Your+Firewall+for+cPanel+Services