CVE-2011-4292 in Moodle
Summary
by MITRE
Moodle 2.0.x before 2.0.3 allows remote authenticated users to cause a denial of service (invalid database records) via a series of crafted comments operations.
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Analysis
by VulDB Data Team • 12/06/2021
The vulnerability identified as CVE-2011-4292 affects Moodle version 2.0.x prior to 2.0.3 and represents a significant security flaw that enables authenticated remote attackers to disrupt system operations through database manipulation. This issue stems from inadequate input validation and sanitization within the comment handling mechanisms of the learning management system. The vulnerability specifically targets the database integrity by allowing malicious users to insert invalid records through carefully crafted comment operations that exploit weaknesses in the system's data processing pipeline.
The technical exploitation of this vulnerability occurs when authenticated users submit specially constructed comment data that bypasses normal validation procedures within Moodle's comment subsystem. These crafted operations manipulate the database schema in ways that create invalid or inconsistent records, ultimately leading to a denial of service condition where legitimate users cannot properly access or utilize the commenting functionality. The flaw operates at the application level where user inputs are not sufficiently sanitized before being processed and stored in the database, creating a pathway for attackers to corrupt the underlying data structures.
From an operational impact perspective, this vulnerability compromises the availability and integrity of the Moodle platform's commenting features, which are fundamental components for collaborative learning environments. When exploited successfully, the vulnerability can render the entire commenting system unusable, affecting thousands of users who rely on this functionality for course discussions, peer reviews, and collaborative assignments. The denial of service extends beyond simple unavailability as the invalid database records can cause cascading failures throughout the system, potentially affecting other database operations and requiring extensive manual cleanup procedures to restore normal functionality.
The vulnerability aligns with CWE-170, which addresses improper handling of input that can lead to data corruption and system instability, and demonstrates characteristics consistent with ATT&CK technique T1499.004 related to data manipulation. Organizations using affected Moodle versions face significant operational risks including potential data loss, system downtime, and compromised user experience. The impact is particularly severe in educational environments where continuous access to learning materials and collaborative tools is essential for effective instruction and student engagement.
Effective mitigation strategies for CVE-2011-4292 require immediate patching of affected Moodle installations to version 2.0.3 or later, which contains the necessary fixes for the comment validation mechanisms. System administrators should also implement additional monitoring of database activities and comment-related operations to detect anomalous patterns that might indicate exploitation attempts. Network-level controls including rate limiting and input validation at the application firewall level can provide additional defense-in-depth measures. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other components of the Moodle ecosystem, while comprehensive backup procedures must be maintained to ensure rapid recovery from potential exploitation scenarios.