In a default configuration, all blocked requests are logged, and you can customize based on your needs. WebKnight 3.0 got an admin web interface where you can customize the rules and perform administration tasks, including statistics.
Shadow Daemon detect, record, and prevent web attacks by filtering request from malicious parameters. It comes with an own interface where you can perform administration and manage this WAF. It supports PHP, Perl & Python language framework.
It can detect the following attacks.
Local/remote file inclusion
Open source is free, but you don’t get support means you need to rely on your expertise and community support. So if you are looking for the commercial WAF, then you may refer the following one.