WAF stands for Web Application Firewall. A WAF is a firewall that protects web applications by monitoring specific HTTP traffic from a web service. Notably, the main function of a web application firewall is to filter, monitor and block malicious traffic to and from web services.

Moreover, the Web Application Firewall protects web applications from attacks. These attacks include Cross-site forgery, Cross-site scripting (XSS), file inclusion, broken access control, SQL injections, cookie poisoning, improper system configuration etc.

Again, this firewall is like a shield between a web application and the internet. But, it does not defend your site from all types of attacks. As well as the Web Application Firewalls can come in the form of software, an appliance, or delivered as-a-service. Similarly, a Web Application Firewall operates through a set of rules often called policies. The policies protect against vulnerabilities in the application by filtering out malicious traffic. Policies can be customized to meet the unique needs of your web application or set of web applications.

You can implement a Web Application Firewall in three different ways as – Host-based WAF, Network-based WAF, and Cloud-based WAF. Furthermore, the Web Application Firewall functions with a set of rules called policies. It works based on a blocklist and aims at protecting against malicious attacks.