Description:
------------
In a system with all error message unactivated for security reason (I.E Production server), it remains possible to reactivate the error messages for a malicious user 
having the ability to execute code although functions error_reporting()/ini_set() be disabled, with the set_error_handler() is used.

Test script:
---------------
<?php

echo phpversion();

echo "<br />";
	
function myErrorHandler($errno, $errstr, $errfile, $errline) {
    var_dump($errno);
    var_dump($errstr);
    var_dump($errfile);
    var_dump($errline);
    return true;
  }

$old_error_handler = set_error_handler("myErrorHandler");

lolel;