ModSecurity is a potent web app layer firewall for Apache web servers. It monitors the entire HTTP traffic to a site without affecting its overall performance and if it detects an intrusion attempt, it prevents it. The firewall furthermore maintains a more thorough log for the website visitors than any web server does, so you will manage to keep an eye on what's going on with your Internet sites better than if you rely merely on standard logs. ModSecurity works with security rules based on which it stops attacks. For instance, it recognizes whether someone is attempting to log in to the administrator area of a given script several times or if a request is sent to execute a file with a certain command. In such instances these attempts set off the corresponding rules and the firewall program blocks the attempts instantly, and then records detailed info about them in its logs. ModSecurity is amongst the very best software firewalls out there and it could easily protect your web applications against many threats and vulnerabilities, particularly if you don’t update them or their plugins often.