These functions can be potentially dangerous in some scenarios for the security of your scripts and server you can always disable them.
Run the below command for the PHP versions you need to disable those functions.
PHP switcher :
echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /usr/local/php/php.d/disabled_function.ini
PHP-CGI selector :
echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php53/usr/php/php.d/disabled_function.ini echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php54/usr/php/php.d/disabled_function.ini echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php55/usr/php/php.d/disabled_function.ini echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php56/usr/php/php.d/disabled_function.ini echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php70/usr/php/php.d/disabled_function.ini echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php71/usr/php/php.d/disabled_function.ini echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php72/usr/php/php.d/disabled_function.ini echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php73/usr/php/php.d/disabled_function.ini
PHP_FPM Selector :
** Don't forget to restart php-fpm after changes
echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php-fpm53/usr/php/php.d/disabled_function.ini && service php-fpm53 restart echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php-fpm54/usr/php/php.d/disabled_function.ini && service php-fpm54 restart echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php-fpm55/usr/php/php.d/disabled_function.ini && service php-fpm55 restart echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php-fpm56/usr/php/php.d/disabled_function.ini && service php-fpm56 restart echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php-fpm70/usr/php/php.d/disabled_function.ini && service php-fpm70 restart echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php-fpm71/usr/php/php.d/disabled_function.ini && service php-fpm71 restart echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php-fpm72/usr/php/php.d/disabled_function.ini && service php-fpm72 restart echo "disable_functions = exec, system, popen, proc_open, shell_exec, passthru, show_source" > /opt/alt/php-fpm73/usr/php/php.d/disabled_function.ini && service php-fpm73 restart
To enable it back, simply delete disabled_function.ini file for the PHP version you want and restart apache/php-fpm.