Cross-site scripting(XSS) is a type of computer security vulnerability tipically found in Web application. XSS enables attackers to inject client-side scripts into Web pages viewed by other users. HTML tag attribute 'href' is used to set target url. Attackers can use 'href' attribute with 'vbscript:' protocol to implement XSS attack. This rule detects 'href' attribute with 'vbscript:' protocol in HTTP request. This rule supports to defend the A3: Injection of OWASP Top 10 - 2021. Other reference:None