CVE-2011-4295 in moodle
Summary
by MITRE
The moodle_enrol_external:role_assign function in enrol/externallib.php in Moodle 2.0.x before 2.0.4 and 2.1.x before 2.1.1 does not have an authorization check, which allows remote authenticated users to gain privileges by making a role assignment.
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Analysis
by VulDB Data Team • 12/06/2021
The vulnerability described in CVE-2011-4295 represents a critical authorization flaw within the Moodle learning management system that affects versions prior to 2.0.4 and 2.1.1. This issue resides in the moodle_enrol_external:role_assign function located within the enrol/externallib.php file, which serves as a critical component for external enrollment operations. The flaw stems from the absence of proper access control verification mechanisms that should validate whether authenticated users possess sufficient privileges to perform role assignment operations within the system. This oversight creates a significant security gap that can be exploited by malicious actors who have already gained authentication credentials to the platform.
The technical implementation of this vulnerability demonstrates a failure in the principle of least privilege enforcement within the Moodle authorization framework. When users authenticate to the system, they should only be granted permissions appropriate to their roles and capabilities. However, the absence of authorization checks in the external enrollment library means that any authenticated user can potentially manipulate role assignments regardless of their actual permissions. This flaw operates at the application logic level and constitutes a direct violation of proper access control mechanisms as defined by the Common Weakness Enumeration standard under CWE-284 which addresses improper access control vulnerabilities.
The operational impact of this vulnerability extends far beyond simple privilege escalation as it enables attackers to fundamentally alter the security posture of the entire Moodle installation. An authenticated attacker could assign administrative roles to themselves or other users, effectively bypassing the intended role-based access controls that protect sensitive system functions and data. This capability allows for complete compromise of the learning management system, enabling unauthorized modifications to course content, user management, system configurations, and potentially leading to data breaches or complete system takeover. The vulnerability particularly affects organizations relying on Moodle for educational content management where unauthorized access to administrative functions could result in significant educational and security consequences.
Security professionals should implement immediate mitigations including upgrading to the patched versions of Moodle 2.0.4 and 2.1.1 as recommended by the vendor. Organizations should also conduct thorough security assessments of their Moodle installations to identify any potential exploitation attempts and ensure proper access control configurations are in place. The vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and privilege escalation through unauthorized access to system resources. Additionally, this flaw demonstrates the importance of implementing comprehensive input validation and access control checks as outlined in the OWASP Top Ten security principles, particularly focusing on proper authorization mechanisms and the prevention of unauthorized privilege escalation attacks that can lead to complete system compromise.