PHP Manual . ... With PHP security, there are two sides to error reporting. ... For example, if an attacker had gleaned information about a page based on a prior form submission, they may attempt to override variables, or modify them: . ... For example, the very style of a generic PHP error indicates a system is running PHP. ... One way of catching this issue ahead of time is to make use of PHP's own error_reporting() , to help you secure your code and find variable usage that may be dangerous. ...