Quiz And Survey Master < 7.1.18 – Reflected Cross-Site Scripting (XSS) | CVE 2021-24368

Description

The plugin did not sanitise or escape its result_id parameter when displaying an existing quiz result page, leading to a reflected Cross-Site Scripting issue. This could allow for privilege escalation by inducing a logged in admin to open a malicious link

Proof of Concept

https://example.com/quiz/test-quiz/?result_id=1597bc5d9f9a2c9659152522904df0c0%3C%22%3E%3Cscript%3Ealert(document.domain)%3C/script%3E

Reproduction steps:

1) Create a quiz.
2) In the "results pages" tab add the %RESULT_LINK% template to display a link to your result when finishing the quiz.
3) Publish your quiz or click the preview button.
4) Take the quiz and copy your results link:

format: https://[wp-host]/quiz/[quiz-name]/?result_id=[result_id]

5) Append <"><script>alert(document.domain)</script> to the result_id and reload the page.

Note (WPScanTeam): As the affected function is hooked to the wp_head action, only the result_id is required to perform the attack, no need to go to the quiz page, ie https://example.com/?result_id=1597bc5d9f9a2c9659152522904df0c0%3C%22%3E%3Cscript%3Ealert(document.domain)%3C/script%3E