CVE-2011-4291 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 ratings operations.
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Analysis
by VulDB Data Team • 12/06/2021
The vulnerability identified as CVE-2011-4291 affects Moodle version 2.0.x before 2.0.3 and represents a significant security flaw that enables authenticated remote attackers to disrupt system operations through carefully constructed database manipulation techniques. This issue stems from inadequate input validation and sanitization within the rating system functionality, creating a pathway for malicious users to inject malformed data that can corrupt database records and ultimately lead to denial of service conditions. The vulnerability specifically targets the rating operations module where users can provide feedback and evaluations within the learning management system environment.
The technical implementation of this vulnerability exploits weaknesses in the database transaction handling mechanisms within Moodle's rating subsystem. When authenticated users submit crafted rating operations, the system fails to properly validate the input data before processing and storing it in the database. This lack of proper validation allows attackers to manipulate the rating records in ways that create invalid database entries, which can subsequently cause cascading failures throughout the system. The flaw operates at the database interaction layer where legitimate rating operations are processed, making it particularly dangerous as it leverages the normal functionality of the platform to execute malicious activities.
From an operational impact perspective, this vulnerability creates substantial risks for educational institutions and organizations relying on Moodle for their learning management needs. The denial of service condition can render rating functionality completely inoperative, preventing legitimate users from providing course feedback, assessments, or peer evaluations that are fundamental to the platform's educational value. Additionally, the invalid database records created by this attack can lead to data corruption that may require extensive manual cleanup or system restoration procedures. The vulnerability also represents a potential vector for more sophisticated attacks that could leverage the database manipulation capabilities to access sensitive information or escalate privileges within the system.
Organizations should implement immediate mitigations including updating to Moodle version 2.0.3 or later, which contains the necessary patches to address the input validation issues. Network segmentation and access controls should be strengthened to limit the number of authenticated users with rating privileges, while monitoring systems should be deployed to detect unusual rating activity patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-170, which addresses improper handling of input data that can lead to invalid data processing, and corresponds to ATT&CK technique T1499.004 for denial of service through data manipulation. Regular database integrity checks and automated backup procedures should be established to ensure rapid recovery capabilities in case of successful exploitation, while security awareness training for administrators can help identify potential attack indicators. The patched version addresses the core validation issues by implementing proper input sanitization and database transaction handling, ensuring that all rating operations are properly validated before being committed to the database.