Disable dangerous PHP functions and improve PHP security - CWP Centos, debian, ubuntu

In this tutorial we'll learn how you can disable dangerous PHP functions. Disabling dangerous PHP functions can help improve the security of your web application by preventing potential exploits and attacks. However, it's important to be cautious when disabling functions, as it may impact the functionality of your application. Only disable functions that are truly unnecessary and represent a significant security risk. Here are some steps you can take to disable dangerous PHP functions:

Use PHP Configuration (php.ini): Many PHP functions can be disabled or restricted through the PHP configuration file (php.ini). Access to this file is usually restricted to server administrators, so you may need to contact your hosting provider or server administrator to make changes.

Using php.ini or .user.ini :

Look or add the disable_functions directive in the php.ini or in .user.ini file and list/add the functions you want to disable, separated by commas. For example:

disable_functions = exec,system,passthru,popen,proc_open,shell_exec

**you need to restart Apache or php-fpm service after you added this directive.

Using .htaccess when using Apache php DSO - mod_php module : 

Use .htaccess (Apache): If you're using the Apache web server, you can also disable PHP functions via the .htaccess file in your web application's root directory. However, this method requires the "mod_php" module to be enabled, and you should have the necessary permissions to modify .htaccess.

Add the following line to your .htaccess file to disable a function:

php_flag disable_functions "exec, system, passthru, popen, proc_open, shell_exec"

**restart Apache service after you've added this directive.

Please note : Regularly update your PHP version and libraries, apply security patches to your CMS/scripts, and follow secure coding practices to build a robust and secure web application