How To Create Web Application Firewall

The WAF or web application firewall will follow either a negative or positive security model as far as developing security policy for an application goes. When you create a web application firewall using a positive security model, it will ensure that only the "good" traffic passes through it. All other traffic will be automatically blocked from entering. When you use a negative security model for creating the WAF, it will allow all the traffic to pass through and try to block the malicious traffic.

There are also some WAF implementations which seek to use both these security models. When you use the positive model the WAF will probably need more tuning and configurations. When you use Web Application Firewall with negative security model, you will have to depend more on behavioral learning. The WAF can also operate in multiple modes. The vendor names for these modes and their supports may vary; this is why it is necessary to check for the details of every product when you want a certain mode. Every mode will also have its share of advantages and disadvantages and organizations must therefore assess to get the right fit suited to their needs.

The WAF is typically created in a proxy fashion right in front of applications in a way that they are unable to view all the traffic. They get to monitor the traffic before the traffic reaches the application and so the WAF can evaluate the requests before these get passed on. This is the edge which the WAFs enjoy compared to regular firewalls. So, the WAF thus created will not only be successful in detecting attacks which are found to be common in web application settings; they are also able to detect or prevent the new and unknown kinds of attacks. They will watch for the unusual or unprecedented patterns in traffic and accordingly alert or defend against these attacks. For instance, when a WAF detects that a specific application is giving back more data than it is meant to, it can send out an alert and block it.