CVE-2021-24186 in Tutor LMS Plugin
Summary
by MITRE • 04/06/2021
The tutor_answering_quiz_question/get_answer_by_id function pair 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-2021-24186 affects the Tutor LMS WordPress plugin, specifically targeting the tutor_answering_quiz_question/get_answer_by_id function pair within versions prior to 1.8.3. This represents a critical security flaw that exposes online educational platforms to unauthorized data access and potential system compromise. The vulnerability manifests as a UNION-based SQL injection attack vector that can be exploited by authenticated users, specifically students within the learning management system environment.
The technical flaw stems from improper input validation and sanitization within the quiz question answering functionality of the Tutor LMS plugin. When students access quiz answers through the get_answer_by_id endpoint, the plugin fails to adequately sanitize user-supplied parameters before incorporating them into SQL database queries. This allows malicious actors to inject crafted SQL commands that can manipulate the database query execution flow. The UNION-based approach enables attackers to combine their malicious SQL fragments with legitimate database queries, potentially extracting sensitive information from underlying database tables.
The operational impact of this vulnerability extends beyond simple data theft, as it provides attackers with the capability to escalate privileges and access confidential educational data. Students who exploit this vulnerability could potentially retrieve other users' personal information, quiz answers, course materials, and administrative credentials stored within the database. The vulnerability is particularly concerning in educational environments where sensitive student data, academic records, and institutional information are stored. The attack surface is widened by the fact that any authenticated user can potentially exploit this flaw, making it accessible to both malicious students and those with insider access.
The vulnerability aligns with CWE-89, which specifically addresses SQL injection flaws in software applications. This categorization indicates that the flaw represents a classic database injection attack vector that can be leveraged to bypass authentication mechanisms, extract confidential data, and potentially execute arbitrary commands on the underlying database server. From an ATT&CK framework perspective, this vulnerability maps to techniques such as T1071.004 (Application Layer Protocol: DNS) and T1566 (Phishing) as attackers may use the compromised system to gather intelligence or launch further attacks. The exploitation process typically involves crafting malicious input parameters that trigger the SQL injection, allowing attackers to extract data through UNION-based queries that can access multiple database tables.
Mitigation strategies for CVE-2021-24186 require immediate patching of the Tutor LMS plugin to version 1.8.3 or later, which contains the necessary security fixes. Organizations should also implement proper input validation and parameterized queries throughout their web applications to prevent similar vulnerabilities from occurring in other components. Network monitoring should be enhanced to detect unusual database query patterns that may indicate exploitation attempts. Additionally, access controls should be reviewed to ensure that students only have access to appropriate data within the learning management system, and regular security audits should be conducted to identify and remediate similar vulnerabilities across all educational technology platforms.