ModSecurity is a potent web app layer firewall for Apache web servers. It monitors the whole HTTP traffic to a website without affecting its functionality and if it discovers an intrusion attempt, it prevents it. The firewall also keeps a more detailed log for the site visitors than any web server does, so you'll manage to monitor what's happening with your Internet sites a lot better than if you rely merely on standard logs. ModSecurity uses security rules based on which it prevents attacks. For instance, it identifies whether anyone is attempting to log in to the administrator area of a particular script several times or if a request is sent to execute a file with a particular command. In these circumstances these attempts trigger the corresponding rules and the firewall program hinders the attempts instantly, and then records in-depth information about them within its logs. ModSecurity is one of the best software firewalls on the market and it can easily protect your web applications against a large number of threats and vulnerabilities, particularly if you don’t update them or their plugins often.