Information
Requiring a boot password upon execution of the boot loader will prevent an unauthorized user from entering boot parameters or changing the boot partition. This prevents users from weakening security (e.g. turning off SELinux at boot time).
Solution
Create an encrypted password with grub-md5-crypt:
# grub-md5-crypt
Password: <password>
Retype Password: <password>
<encrypted-password>
Copy and paste the <encrypted-password> into the global section of /boot/grub/grub.conf:
password --md5 <encrypted-password>