These are some tips that I picked up over the years working with cPanel & WHM.
Set Unlimited email quota in cPanel
In cPanel email quota is saved for each domain name in a quota file located inside /home/username/etc/domain.com/
So to set an unlimited quota for an email account simply remove the numbers from this file:
phpinfo.php file for default PHP version
Often when checking limits or extensions we find ourselves creating a phpinfo.php file inside the website directory. But did you know that there is also a pre-made phpinfo.php file visible to cpanel users? By navigating to phpinfo.php
NOTE: this file will output information only for the default PHP version set in WHM.
Another interesting file that is only accessible to logged-in cpanel users is the env.cgi file that displays all environmental variables such as IP, username, password, cp_session, etc.
For more information read: cPanel information disclosure via env.cgi file
Password strength checker
Another script that is used by cpanel to check password strength is passwordstrength.cgi – by calling this script and adding password= parameter in the URL, a logged in user can check his password strength.
Add your password at the end and the script will simply output the strength in the range from 0 to 100.