Lab: DOM XSS in jQuery anchor `href` attribute sink using `location.search` source

APPRENTICE

This lab contains a DOM-based cross-site scripting vulnerability in the submit feedback page. It uses the jQuery library's $ selector function to find an anchor element, and changes its href attribute using data from location.search.

To solve this lab, make the "back" link alert document.cookie.

Access the lab

Solution

On the Submit feedback page, change the query parameter returnPath to / followed by a random alphanumeric string.
Right-click and inspect the element, and observe that your random string has been placed inside an a href attribute.
Change returnPath to:
javascript:alert(document.cookie)
Hit enter and click "back".