Stored And Reflected XSS Vulnerabilities In Limesurvey (Cve-2019-16172, Cve-2019-16173)

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

critical

Found

08.23.2019

By

Andreas Kolbeck (Office Munich) | Haintz (Office Vienna) | SEC Consult Vulnerability Lab

XSS vulnerabilities within LimeSurvey enable an attacker to perform unauthorized actions in the name of another logged-in user, and attack other users of the web application with JavaScript code, browser exploits or Trojan horses.

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

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

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:

$host/index.php/admin/survey src=x%20onerror=%22alert(document.cookie)%22%3E&sa=listquestions&sort=question

If the URL schema is configured differently the following payload works:

$host/index.php= 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 (see solution)
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 advisorySolution

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