ModSecurity is a potent web application layer firewall for Apache web servers. It monitors the whole HTTP traffic to a site without affecting its functionality and when it identifies an intrusion attempt, it blocks it. The firewall also maintains a more detailed log for the website visitors than any web server does, so you'll manage to monitor what's happening with your sites a lot better than if you rely simply on conventional logs. ModSecurity uses security rules based on which it prevents attacks. For instance, it detects whether someone is attempting to log in to the administration area of a given script several times or if a request is sent to execute a file with a particular command. In such circumstances these attempts set off the corresponding rules and the software blocks the attempts instantly, after that records detailed details about them within its logs. ModSecurity is one of the most effective software firewalls out there and it can easily protect your web applications against a huge number of threats and vulnerabilities, particularly in case you don’t update them or their plugins frequently.