SEC Consult Vulnerability Lab Security Advisory < 20190912-0 >  
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  
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  
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."  
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:  
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:  
If the URL schema is configured differently the following payload works:  
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  
2019-09-02: Fixes available:  
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  
Update to version 3.17.15 or higher:  
The vendor provides a detailed list of changes here:  
No workaround available.  
Advisory URL:  
SEC Consult Vulnerability Lab  
SEC Consult  
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EOF A. Kolbeck / @2019