SEC Consult Vulnerability Lab Security Advisory < 20190912-0 >
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              title: Stored and reflected XSS vulnerabilities
            product: LimeSurvey
 vulnerable version: <= 3.17.13
      fixed version: =>3.17.14
         CVE number: CVE-2019-16172, CVE-2019-16173
             impact: medium
           homepage: https://www.limesurvey.org/
              found: 2019-08-23
                 by: Andreas Kolbeck (Office Munich)
                     David Haintz (Office Vienna)
                     SEC Consult Vulnerability Lab

                     An integrated part of SEC Consult
                     Europe | Asia | North America

                     https://www.sec-consult.com

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Vendor description:
-------------------
"LimeSurvey is the tool to use for your online surveys. Whether you are
conducting simple questionnaires with just a couple of questions or advanced
assessments with conditionals and quota management, LimeSurvey has got you
covered. LimeSurvey is 100% open source and will always be transparently developed.
We can help you reach your goals."

Source: https://www.limesurvey.org/


Business recommendation:
------------------------
LimeSurvey suffered from a vulnerability due to improper input
and output validation. By exploiting this vulnerability an attacker could:
    1. Attack other users of the web application with JavaScript code,
       browser exploits or Trojan horses, or
    2. perform unauthorized actions in the name of another logged-in user.

The vendor provides a patch which should be installed immediately.
Furthermore, a thorough security analysis is highly recommended as only a
short spot check has been performed and additional issues are to be expected.


Vulnerability overview/description:
-----------------------------------
1) Stored and reflected XSS vulnerabilities
LimeSurvey suffers from a stored and reflected cross-site scripting vulnerability,
which allows an attacker to execute JavaScript code with the permissions of the victim.
In this way it is possible to escalate privileges from a low-privileged account e.g.
to "SuperAdmin".


Proof of concept:
-----------------
1) Stored and reflected XSS vulnerabilities
Example 1 - Stored XSS (CVE-2019-16172):
The attacker needs the appropriate permissions in order to create new survey groups.
Then create a survey group with a JavaScript payload in the title, for example:

test<svg/onload=alert(document.cookie)>

When the survey group is being deleted, e.g. by an administrative user, the JavaScript
code will be executed as part of the "success" message.


Example 2 - Reflected XSS (CVE-2019-16173):
The following proof of concept prints the current CSRF token cookie which contains the
CSRF token. The parameter "surveyid" is not filtered properly:

http://$host/index.php/admin/survey?mandatory=1&sid=xxx&surveyid=xxx%22%3E%3Cimg%20
src=x%20onerror=%22alert(document.cookie)%22%3E&sa=listquestions&sort=question


If the URL schema is configured differently the following payload works:
http://$host/index.php?r=admin/survey&mandatory=1&sid=xxx&surveyid=
xxx"><img%20src=x%20onerror="alert(document.cookie)">&sa=listquestions&sort=question


Vulnerable / tested versions:
-----------------------------
The vulnerabilities have been verified to exist in version 3.17.9 and the latest
version 3.17.13. It is assumed that older versions are affected as well.


Vendor contact timeline:
------------------------
2019-08-29: Contacting vendor through https://bugs.limesurvey.org/view.php?id=15204
2019-09-02: Fixes available:
            https://github.com/LimeSurvey/LimeSurvey/commit/32d6a5224327b246ee3a2a08500544e4f80f9a9a
            https://github.com/LimeSurvey/LimeSurvey/commit/f1c1ad2d24eb262363511fcca2e96ce737064006
2019-09-02: Release of LimeSurvey v3.17.14 which fixes the security issues
2019-09-03: Release of LimeSurvey v3.17.15 bug fix
2019-09-12: Coordinated release of security advisory


Solution:
---------
Update to version 3.17.15 or higher:
https://www.limesurvey.org/stable-release

The vendor provides a detailed list of changes here:
https://www.limesurvey.org/limesurvey-updates/2188-limesurvey-3-17-14-build-190902-released


Workaround:
-----------
No workaround available.


Advisory URL:
-------------
https://www.sec-consult.com/en/vulnerability-lab/advisories/index.html


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

SEC Consult Vulnerability Lab

SEC Consult
Europe | Asia | North America

About SEC Consult Vulnerability Lab
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recommendation about the risk profile of new technologies.

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EOF A. Kolbeck / @2019