A Web Application Firewall (WAF) is probably one of the most popular preventive and/or detective security controls for web applications today. Amazon Web Services (AWS) has recently launched its own WAF service, raising some questions from Gartner. Garters Magic Quadrant estimates that the global WAF market size is as big as $420 million, with 24 percent annual growth. By 2020, more than 60 percent of public web applications will be protected by a WAF.”]