ModSecurity is an effective firewall for Apache web servers that is employed to prevent attacks against web apps. It monitors the HTTP traffic to a given website in real time and prevents any intrusion attempts the instant it detects them. The firewall uses a set of rules to do this - as an example, attempting to log in to a script admin area without success a few times activates one rule, sending a request to execute a certain file that may result in accessing the Internet site triggers another rule, etcetera. ModSecurity is one of the best firewalls around and it will secure even scripts that aren't updated often as it can prevent attackers from using known exploits and security holes. Very detailed info about each intrusion attempt is recorded and the logs the firewall maintains are a lot more specific than the standard logs provided by the Apache server, so you could later examine them and decide whether you need to take extra measures so as to increase the security of your script-driven sites.