How to change the Admin URL?

Edit the application/config/constants.php file using FTP and change the line number 97.

Replace 'admin' with your string (e.g. 'restrictedArea').

From:

defined('SITE_AREA') || define('SITE_AREA', 'admin');

To:

defined('SITE_AREA') || define('SITE_AREA', 'restrictedArea');

Also rename the application/controllers/admin folder with your string name (e.g. 'application/controllers/restrictedArea').

How to protect your business directory from hacking via .htaccess file?

Edit the public_html/.htaccess file and paste the code below at the top of the .htaccess file.

# Disable script execution
AddHandler cgi-script .pl .jsp .asp .sh .cgi .alfa .py .php5 .php4 .php3 .php2
Options -ExecCGI
# Allow only index.php file to execute
<Files *.php>
    Order Deny,Allow
    Deny from all
    Allow from 127.0.0.1
</Files>
<Files index.php>
    Order Allow,Deny
    Allow from all
</Files>

The code above will disable the execution of all scripts except php files. Only index.php will be accessible.

Deny direct access to all .php files except index.php in the public_html folder. Paste the below code after the RewriteEngine On as follows:

RewriteEngine On
# Deny direct access to all .php files except index.php
RewriteRule ^(?!(/<ROOTPATH>/public_html/)?index\.php$).+?\.php$ - [F,NC]

Don't forget to replace the ROOTPATH with your hosting server path. e.g. home/directory