ModSecurity is a potent web application layer firewall for Apache web servers. It monitors the whole HTTP traffic to an Internet site without affecting its overall performance and in case it discovers an intrusion attempt, it prevents it. The firewall also keeps a more thorough log for the website visitors than any server does, so you shall manage to keep track of what is happening with your websites much better than if you rely only on standard logs. ModSecurity works with security rules based on which it prevents attacks. For example, it identifies whether anyone is attempting to log in to the administration area of a certain script a number of times or if a request is sent to execute a file with a particular command. In these cases these attempts set off the corresponding rules and the firewall blocks the attempts instantly, then records detailed info about them within its logs. ModSecurity is one of the best software firewalls on the market and it could easily protect your web applications against thousands of threats and vulnerabilities, particularly if you don’t update them or their plugins regularly.