CVE-2011-4303 in Moodle
Summary
by MITRE
lib/db/upgrade.php in Moodle 2.0.x before 2.0.5 and 2.1.x before 2.1.2 does not set the correct registration_hubs.secret value during installation, which allows remote attackers to bypass intended access restrictions by leveraging the hubs feature.
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Analysis
by VulDB Data Team • 12/05/2021
The vulnerability described in CVE-2011-4303 affects Moodle learning management systems version 2.0.x before 2.0.5 and 2.1.x before 2.1.2, specifically within the database upgrade process located in lib/db/upgrade.php. This flaw represents a critical security oversight that undermines the system's access control mechanisms through improper configuration of the registration_hubs.secret parameter during the installation phase. The issue stems from the fact that during the upgrade process, the system fails to properly establish the secret value required for hub registration functionality, creating a persistent security weakness that can be exploited by remote attackers.
The technical implementation of this vulnerability involves the improper handling of the registration_hubs.secret configuration parameter which serves as a cryptographic secret for authenticating communication with Moodle hubs. When the upgrade.php script executes during installation, it fails to correctly initialize this secret value, leaving it either unset or with a predictable default value. This misconfiguration allows attackers to bypass intended access restrictions by leveraging the hub registration feature, which is designed to facilitate communication between Moodle installations and central hub servers. The flaw operates at the configuration management level and directly impacts the system's ability to enforce proper authentication boundaries.
From an operational impact perspective, this vulnerability exposes Moodle installations to unauthorized access and potential exploitation by remote attackers who can leverage the hub feature to gain elevated privileges or access restricted functionality. The vulnerability essentially creates a backdoor mechanism through which attackers can bypass normal authentication procedures, potentially allowing them to perform administrative actions or access sensitive system information. This represents a significant compromise of the system's integrity and confidentiality, as it allows unauthorized parties to exploit the legitimate hub registration functionality for malicious purposes.
The vulnerability aligns with CWE-284, which addresses improper access control, and relates to the broader category of weak configuration management issues. From an ATT&CK framework perspective, this weakness maps to techniques involving privilege escalation and initial access through configuration flaws. The vulnerability demonstrates poor input validation and configuration management practices, as the system should have enforced proper initialization of security-critical parameters during the upgrade process. Organizations using affected Moodle versions face significant risk of unauthorized access and potential data compromise, as the flaw persists through the system's operational lifecycle until properly patched.
The recommended mitigation strategy involves upgrading to Moodle versions 2.0.5 or 2.1.2 and later, which contain the necessary fixes to properly initialize the registration_hubs.secret parameter during installation. Administrators should also conduct thorough security audits of their Moodle installations to ensure proper configuration of all security parameters, particularly those related to hub registration and external communication. Additionally, implementing network-level controls and monitoring for unusual hub registration activities can provide additional layers of defense against exploitation attempts. Organizations should also verify that their upgrade processes properly initialize all security-critical configuration parameters to prevent similar issues in future deployments.