CVE-2021-24181 in Tutor LMS
Summary
by MITRE • 04/06/2021
The tutor_mark_answer_as_correct AJAX action from the Tutor LMS – eLearning and online course solution WordPress plugin before 1.7.7 was vulnerable to blind and time based SQL injections that could be exploited by students.
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Analysis
by VulDB Data Team • 04/10/2021
The vulnerability CVE-2021-24181 affects the Tutor LMS WordPress plugin, specifically targeting the tutor_mark_answer_as_correct AJAX action within versions prior to 1.7.7. This represents a critical security flaw that undermines the integrity of online learning platforms by exposing a blind and time-based SQL injection vector. The vulnerability is particularly concerning because it allows authenticated users with student-level privileges to exploit the system, demonstrating a significant privilege escalation risk within the eLearning environment.
The technical flaw stems from improper input validation and sanitization within the AJAX handler that processes student answer marking functionality. When students submit answers through the tutor_mark_answer_as_correct endpoint, the plugin fails to adequately sanitize user-supplied data before incorporating it into SQL queries. This oversight creates conditions where malicious input can manipulate the underlying database queries, enabling attackers to infer database structure through time-based delays or extract information through blind injection techniques. The vulnerability operates at the database layer, making it particularly dangerous as it can bypass application-level security controls.
The operational impact of this vulnerability extends beyond simple data theft, as it can enable attackers to manipulate course content, alter student grades, and potentially gain unauthorized access to sensitive educational data. Students who exploit this vulnerability can construct malicious payloads that cause the database server to execute arbitrary commands or return specific information through carefully crafted time delays. This type of injection attack can be particularly insidious because it allows for gradual information extraction without immediate detection, making it difficult for administrators to identify compromised systems. The vulnerability affects the core functionality of the eLearning platform, potentially compromising the entire educational ecosystem managed through Tutor LMS.
Mitigation strategies should prioritize immediate plugin updates to version 1.7.7 or later, which contain the necessary patches addressing the SQL injection vulnerabilities. Organizations should implement comprehensive input validation measures and employ parameterized queries to prevent similar issues in future development cycles. Security monitoring should be enhanced to detect unusual database query patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-89, which categorizes improper neutralization of special elements used in SQL commands, and represents a significant concern under ATT&CK technique T1078 for valid accounts and T1190 for exploitation of remote services. Network segmentation and privileged access controls should be reinforced to limit potential damage from successful exploitation attempts.