Web Application Firewall (WAF) is now generally available in all public cloud regions as part of the Azure Application Gateway WAF SKU. WAF helps protect web applications from common web-based attacks like SQL injection, cross-site scripting attacks, and protocol anomalies. It comes preconfigured with Core Rule Sets to provide protection from many of the threats identified by the Open Web Application Security Project (OWASP) as the top 10 common vulnerabilities.
For more information, refer to the Application Gateway Web Application Firewall documentation.