ModSecurity is an efficient firewall for Apache web servers that is used to prevent attacks toward web applications. It monitors the HTTP traffic to a particular website in real time and stops any intrusion attempts the moment it identifies them. The firewall relies on a set of rules to do that - as an example, trying to log in to a script administrator area unsuccessfully many times triggers one rule, sending a request to execute a particular file which could result in accessing the website triggers a different rule, and so on. ModSecurity is amongst the best firewalls available on the market and it will protect even scripts that are not updated frequently as it can prevent attackers from employing known exploits and security holes. Very thorough information about each intrusion attempt is recorded and the logs the firewall keeps are a lot more comprehensive than the conventional logs provided by the Apache server, so you may later examine them and determine if you need to take additional measures so as to improve the protection of your script-driven websites.