ModSecurity is a highly effective web application layer firewall for Apache web servers. It monitors the entire HTTP traffic to a website without affecting its operation and in case it identifies an intrusion attempt, it blocks it. The firewall additionally keeps a more detailed log for the site visitors than any web server does, so you shall manage to monitor what's going on with your websites better than if you rely only on conventional logs. ModSecurity uses security rules based on which it prevents attacks. For instance, it identifies whether someone is trying 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 certain command. In these cases these attempts set off the corresponding rules and the firewall blocks the attempts immediately, and then records in-depth details about them inside its logs. ModSecurity is one of the most effective software firewalls on the market and it can protect your web apps against many threats and vulnerabilities, particularly if you don’t update them or their plugins often.