ModSecurity is a highly effective firewall for Apache web servers which is used to prevent attacks toward web applications. It keeps track of the HTTP traffic to a particular Internet site in real time and stops any intrusion attempts as soon as it discovers them. The firewall relies on a set of rules to do that - as an illustration, trying to log in to a script administration area unsuccessfully several times sets off one rule, sending a request to execute a particular file which may result in accessing the website triggers another rule, and so on. ModSecurity is one of the best firewalls out there and it'll protect even scripts which are not updated often since it can prevent attackers from using known exploits and security holes. Very comprehensive data about every intrusion attempt is recorded and the logs the firewall keeps are considerably more specific than the standard logs generated by the Apache server, so you may later take a look at them and decide if you need to take more measures so as to enhance the protection of your script-driven sites.