'[FD] CSRF/stored XSS in Quiz And Survey Master (Formerly Quiz Master Next) allows unauthenticated at'

[prev in list] [next in list] [prev in thread] [next in thread] 

List:       full-disclosure
Subject:    [FD] CSRF/stored XSS in Quiz And Survey Master (Formerly Quiz Master Next) allows unauthenticated at
From:       dxw Security <security () dxw ! com>
Date:       2016-12-15 16:06:35
Message-ID: e4c230f800839dcf5f1ed6fe0707e354 () security ! dxw ! com
[Download RAW message or body]

Details
================
Software: Quiz And Survey Master (Formerly Quiz Master Next)
Version: 4.5.4,4.7.8
Homepage: https://wordpress.org/plugins/quiz-master-next/
Advisory report: https://security.dxw.com/advisories/csrfstored-xss-in-quiz-and-survey-master-fo \
                rmerly-quiz-master-next-allows-unauthenticated-attackers-to-do-almost-anything-an-admin-can/

CVE: Awaiting assignment
CVSS: 5.8 (Medium; AV:N/AC:M/Au:N/C:P/I:P/A:N)

Description
================
CSRF/stored XSS in Quiz And Survey Master (Formerly Quiz Master Next) allows unauthenticated \
attackers to do almost anything an admin can

Vulnerability
================
A CSRF vulnerability allows an unauthenticated attacker to add questions to existing quizzes.
The question_name parameter is put into a manually-constructed JavaScript object and escaped \
with esc_js() (php/qmn_options_questions_tab.php line 499). If the user (or attacker) creates a \
new question on a quiz containing “<script>alert(1)</script>” in the question_name field then \
“question: ‘&lt;script&gt;alert(1)&lt;/script&gt;’,” will get output inside the JS object. All \
good so far. However, in js/admin_question.js on line 205, we see this line, as part of some \
JS-generated HTML: jQuery(\'<textarea/>\').html(questions_list[i].question.replace(/\"/g, \
\'\"\').replace(/\'/g, \"\'\")).text()+ This looks okay. We’re creating a TEXTAREA element, \
setting its HTML to the value of the question_name parameter, and extracting the .text() of it. \
If we did jQuery(‘<textarea/>’).html(‘<script>alert(1)</script>’).text() we would get \
“alert(1)” as the output. However, that’s not how inline JavaScript gets parsed. Between a \
<script> and a </script>, the HTML parser actually parses “&lt;” as “&lt;” not as “<“. So if we \
do jQuery(‘<textarea/>’).html(‘&lt;script&gt;alert(1)&lt;/script&gt;’).text() we get \
“<script>alert(1)</script>”. And since “<script>alert(1)</script>” doesn’t appear anywhere in \
the page, Chrome’s reflected XSS mitigation measures are not activated. Thus the stored XSS \
attack can be executed immediately.

Proof of concept
================
Click the submit button on the following page (in a real attack the form can be submitted \
without user interaction): <form method=\"POST\" \
action=\"http://localhost/wp-admin/admin.php?page=mlw_quiz_options&quiz_id=1\"> <input \
type=\"text\" name=\"question_type\" value=\"0\"> <input type=\"text\" name=\"question_name\" \
value=\"&lt;script>alert(1)&lt;/script>\"> <input type=\"text\" name=\"question_submission\" \
value=\"new_question\"> <input type=\"text\" name=\"quiz_id\" value=\"1\">
<input type=\"submit\">
</form>

Mitigations
================
Upgrade to version 4.7.9 or later.

Disclosure policy
================
dxw believes in responsible disclosure. Your attention is drawn to our disclosure policy: \
https://security.dxw.com/disclosure/

Please contact us on security@dxw.com to acknowledge this report if you received it via a third \
party (for example, plugins@wordpress.org) as they generally cannot communicate with us on your \
behalf.

This vulnerability will be published if we do not receive a response to this report with 14 \
days.

Timeline
================

2015-09-14: Discovered
2016-12-07: Reported to vendor via https://quizandsurveymaster.com/contact-us/
2016-12-07: Requested CVE
2016-12-13: Vendor replied
2016-12-14: Vendor reported issue fixed in version 4.7.9
2016-12-15: Advisory published

Discovered by dxw:
================
Tom Adams
Please visit security.dxw.com for more information.

_______________________________________________
Sent through the Full Disclosure mailing list
https://nmap.org/mailman/listinfo/fulldisclosure
Web Archives & RSS: http://seclists.org/fulldisclosure/

[prev in list] [next in list] [prev in thread] [next in thread] 