How to disable PHP functions using PHP disable_functions

Most of the web hosting companies disable dangerous PHP functions for security reasons. You will see the below warning if any PHP function is disabled server-wide.
 

 

Follow the below steps to disable functions using PHP disable_functions.

1. You must log into your Linux server as ‘root’ user or as any user with sudo privileges

2. Run the command ‘php --ini’ to find the path of loaded PHP configuration file
 

 
3. Open PHP configuration using vi editor and scroll down to ‘disable_functions’ line
 

 

 
4. Add the PHP function to disable in disable_functions line. Example: disable_functions = ini_set
 

 
5. Use comma-delimited list of function names to disable multiple PHP functions. Example: disable_functions = ini_set, exec, system

6. Save the php.ini file and exit

7. You must restart the Web server for changes to take effect
 

 
8. Create a phpinfo file to verify functions are disabled
 

 
 

How to Enable the Disabled PHP functions

1. Log into Linux server via SSH as ‘root’ user

2. Run the command ‘php --ini’ to find the location of php.ini

3. Open php.ini using vi editor
 

 
4. Remove all PHP functions in disable_functions line
 

 
5. Save the php.ini file and exit

6. Restart the web server
 

 
7. Create a phpinfo page to verify functions are removed.