[alpha.informatica.com] Expensive DOMXSS

Hi again, The page at https://alpha.informatica.com/assessmentBase/assessment.html contains the following JavaScript: <script> var baseHeaderElement = '<base href="'+ window.location.pathname + '" />'; $('head').append(baseHeaderElement); </script> An attacker can exploit this using a protocol-relative URL. In Chrome, open the following URL and either proxy though Burp or look at the network tab in the dev console: https://alpha.informatica.com//assessmentBase/assessment.html You will see a failed GET request to https://assessmentbase/etc/designs/informatica-com/assessmentform/js/angular.min.js A sufficiently rich attacker can register assessementbase, and make it serve malicious JavaScript, turning this into a reflected XSS vulnerability. This issue was passively identified by burp suite's code analysis engine.