The Web Application Firewall ("WAF") is a Web security protection product provided by Baidu AI Cloud to the users, and can effectively protect against different Web attacks, and assist the users in customizing access rules, and improving the security of business such as the website. The originally-created brand-new WAF technology architecture system can flexibly deploy the WAF instances in each Web business ingress to avoid the embarrassment that hackers bypass the age embarrassment nt to directly attack the source station under the traditional cloud WAF architecture. The integration of big data capabilities in cloud security also enables WAF to better help the customers improve the website security and availability more effectively and quickly.