ModSecurity is an effective firewall for Apache web servers which is employed to stop attacks toward web apps. It keeps track of the HTTP traffic to a given site in real time and prevents any intrusion attempts the instant it discovers them. The firewall relies on a set of rules to do this - for example, attempting to log in to a script admin area unsuccessfully a few times triggers one rule, sending a request to execute a specific file that could result in getting access to the Internet site triggers a different rule, and so on. ModSecurity is one of the best firewalls out there and it will secure even scripts that are not updated regularly as it can prevent attackers from employing known exploits and security holes. Very thorough information about every intrusion attempt is recorded and the logs the firewall keeps are far more comprehensive than the standard logs provided by the Apache server, so you may later examine them and determine if you need to take additional measures so as to increase the protection of your script-driven websites.