ModSecurity is a potent web app layer firewall for Apache web servers. It monitors the whole HTTP traffic to an Internet site without affecting its performance and if it identifies an intrusion attempt, it blocks it. The firewall additionally keeps a more comprehensive log for the site visitors than any web server does, so you'll manage to keep an eye on what's happening with your websites better than if you rely merely on conventional logs. ModSecurity works with security rules based on which it prevents attacks. For instance, it detects whether anyone is trying to log in to the admin area of a given script several times or if a request is sent to execute a file with a particular command. In such cases these attempts set off the corresponding rules and the firewall blocks the attempts in real time, and then records detailed information about them in its logs. ModSecurity is amongst the very best software firewalls on the market and it can easily protect your web applications against a huge number of threats and vulnerabilities, especially if you don’t update them or their plugins regularly.