CVE-2021-24183 in Tutor LMS Plugin
Summary
by MITRE • 04/06/2021
The tutor_quiz_builder_get_question_form AJAX action from the Tutor LMS – eLearning and online course solution WordPress plugin before 1.8.3 was vulnerable to UNION based SQL injection that could be exploited by students.
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Analysis
by VulDB Data Team • 04/10/2021
The vulnerability identified as CVE-2021-24183 affects the Tutor LMS WordPress plugin, specifically targeting the tutor_quiz_builder_get_question_form AJAX action within versions prior to 1.8.3. This represents a critical security flaw that undermines the integrity of educational platform functionality by exposing a pathway for unauthorized data access through SQL injection techniques. The vulnerability exists within the plugin's handling of AJAX requests, which are commonly used for dynamic content updates without full page reloads, making it particularly dangerous as it can be exploited through normal user interactions.
The technical flaw manifests as a UNION-based SQL injection vulnerability that allows attackers to manipulate database queries through crafted input parameters. This type of injection occurs when user-supplied data is directly concatenated into SQL statements without proper sanitization or parameterization. The vulnerability specifically affects the quiz builder component of the Tutor LMS plugin, which is designed to help educators create interactive learning assessments. Attackers can exploit this weakness by crafting malicious payloads that leverage the UNION operator to combine their malicious SQL queries with legitimate database operations, potentially extracting sensitive information from the underlying database.
The operational impact of this vulnerability is significant for educational institutions and online learning platforms that rely on the Tutor LMS plugin. Since the vulnerability can be exploited by students who have access to the platform, it creates an insider threat scenario where legitimate users can gain unauthorized access to sensitive data. This includes potentially exposing student records, quiz results, course materials, and other confidential information stored in the database. The attack vector is particularly concerning because it requires no special privileges beyond standard student access, making it accessible to anyone with legitimate platform credentials.
The vulnerability aligns with CWE-89, which categorizes SQL injection flaws as a fundamental weakness in application security. This classification indicates the severity of the issue and its potential for widespread exploitation across similar platforms. From an ATT&CK framework perspective, this vulnerability maps to T1071.004 for Application Layer Protocol: DNS and T1566 for Phishing, as attackers could potentially use the compromised data to craft more sophisticated attacks or gain additional access privileges. The exploitation of this vulnerability could enable attackers to escalate their privileges within the learning management system, potentially leading to full system compromise.
Mitigation strategies should include immediate patching to version 1.8.3 or later, which addresses the SQL injection vulnerability through proper input validation and parameterized query construction. Organizations should also implement network monitoring to detect suspicious AJAX request patterns that might indicate exploitation attempts. Additional protective measures include restricting AJAX endpoint access through proper authentication checks, implementing web application firewalls, and conducting regular security audits of plugin components. Security teams should also consider implementing database query logging and access controls to limit the potential impact of any successful exploitation attempts, ensuring that even if the vulnerability is exploited, the scope of data access remains limited.