CVE-2016-3729 in Moodle
Summary
by MITRE
The user editing form in Moodle 3.0 through 3.0.3, 2.9 through 2.9.5, 2.8 through 2.8.11, 2.7 through 2.7.13, and earlier allows remote authenticated users to edit profile fields locked by the administrator.
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Analysis
by VulDB Data Team • 12/01/2022
The vulnerability described in CVE-2016-3729 represents a critical access control flaw within the Moodle learning management system that affects multiple versions including 3.0 through 3.0.3, 2.9 through 2.9.5, 2.8 through 2.8.11, 2.7 through 2.7.13, and earlier releases. This issue manifests in the user editing form functionality where authenticated users can bypass administrative restrictions that should prevent modification of profile fields designated as locked by system administrators. The flaw essentially undermines the intended security model of Moodle's user profile management system, allowing unauthorized modifications to occur despite explicit administrative controls. From a cybersecurity perspective, this vulnerability directly violates the principle of least privilege and represents a failure in access control enforcement mechanisms that are fundamental to secure system design.
The technical implementation of this vulnerability stems from insufficient validation checks within the user profile editing component of Moodle's codebase. When administrators configure profile fields as locked, they expect these fields to remain immutable by users regardless of their authentication status. However, the vulnerability allows authenticated users to manipulate the editing form parameters to override these administrative restrictions. This typically occurs through manipulation of form data or direct API calls that bypass the intended validation layers. The flaw operates at the application logic level rather than at network or infrastructure layers, making it particularly challenging to detect through traditional network monitoring approaches. According to CWE classification, this vulnerability maps to CWE-285: Improper Authorization, which specifically addresses situations where the system fails to properly enforce access control policies for authenticated users.
The operational impact of CVE-2016-3729 extends beyond simple data modification, as it creates potential vectors for more sophisticated attacks within educational environments. An attacker who successfully exploits this vulnerability can potentially modify user profile information to include malicious data, create false identities, or manipulate user permissions within the system. This could lead to privilege escalation scenarios where users gain unauthorized access to restricted resources or information. The vulnerability is particularly concerning in educational institutions where Moodle systems handle sensitive student and staff data, as it could enable unauthorized modification of personal information, academic records, or institutional data. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1078: Valid Accounts, as it allows exploitation of legitimate authenticated user accounts to perform unauthorized modifications. The attack chain typically involves initial authentication followed by form manipulation to bypass administrative controls, making it difficult to distinguish from legitimate administrative activities in system logs.
Mitigation strategies for this vulnerability require immediate implementation of security patches provided by Moodle developers, as the issue was addressed through code modifications that properly enforce administrative field locking controls. Organizations should also implement comprehensive monitoring of user profile modification activities, particularly focusing on changes to fields that should remain locked. Network segmentation and access control policies can help limit the scope of potential exploitation, while regular security audits of user management components should be conducted. System administrators should also review and validate existing user profile configurations to ensure that administrative controls are properly enforced. The vulnerability highlights the importance of thorough input validation and access control testing in web applications, particularly those handling sensitive user data. Organizations should consider implementing automated security scanning tools that can detect similar access control flaws in their Moodle installations and other educational technology platforms. Additionally, regular security training for system administrators on the importance of patch management and proper configuration of security controls is essential to prevent exploitation of similar vulnerabilities in the future.