ModSecurity is a powerful firewall for Apache web servers which is used to prevent attacks against web apps. It tracks the HTTP traffic to a particular Internet site in real time and blocks any intrusion attempts the moment it identifies them. The firewall uses a set of rules to do that - as an illustration, attempting to log in to a script admin area unsuccessfully several times sets off one rule, sending a request to execute a certain file which could result in accessing the website triggers a different rule, etc. ModSecurity is among the best firewalls available on the market and it will preserve even scripts that aren't updated often since it can prevent attackers from using known exploits and security holes. Incredibly thorough info about every intrusion attempt is recorded and the logs the firewall maintains are much more specific than the regular logs generated by the Apache server, so you can later examine them and decide if you need to take extra measures in order to increase the security of your script-driven Internet sites.