CVE-2011-4584 in Moodle
Summary
by MITRE
The MNET authentication functionality in Moodle 1.9.x before 1.9.15, 2.0.x before 2.0.6, and 2.1.x before 2.1.3 allows remote authenticated users to impersonate other user accounts by using the Login As feature in conjunction with a remote MNET single sign-on capability, as demonstrated by a Mahara site.
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Analysis
by VulDB Data Team • 12/06/2021
The vulnerability described in CVE-2011-4584 represents a critical authentication flaw within the Moodle learning management system that enables unauthorized account impersonation through sophisticated exploitation of the MNET (Moodle Network) authentication framework. This issue affects multiple versions of Moodle including 1.9.x prior to 1.9.15, 2.0.x prior to 2.0.6, and 2.1.x prior to 2.1.3, indicating a widespread impact across the Moodle ecosystem during that period. The vulnerability specifically targets the interaction between the Login As functionality and the remote MNET single sign-on capability, creating a pathway for authenticated attackers to assume the identities of other users within the system.
The technical exploitation of this vulnerability relies on the improper handling of authentication tokens and session management within the MNET authentication subsystem. When users authenticate through MNET-enabled sites, the system should maintain strict validation of user identities and prevent unauthorized access to other accounts. However, the flaw allows an authenticated user to manipulate the authentication flow by leveraging the Login As feature in conjunction with MNET's remote authentication capabilities. This creates a scenario where attackers can potentially forge authentication requests that appear legitimate to the Moodle system, thereby bypassing normal access controls and gaining unauthorized access to other user accounts.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the integrity of the user authentication system within Moodle. Organizations relying on Moodle for educational or training purposes face significant risks including unauthorized access to student records, course materials, and administrative functions. The vulnerability particularly affects institutions that utilize MNET for federated authentication across multiple Moodle instances or integrate with external systems such as Mahara, which was specifically mentioned as a demonstration platform for this exploit. This cross-platform exploitation capability makes the vulnerability particularly dangerous as it can be leveraged across interconnected educational networks and institutions.
Security researchers have classified this vulnerability under CWE-287 which addresses improper authentication issues, specifically focusing on the weakness in authentication mechanisms that allow unauthorized access to resources. The attack pattern aligns with techniques described in the MITRE ATT&CK framework under the credential access category, where adversaries exploit legitimate credentials and authentication mechanisms to gain access to additional accounts. The vulnerability demonstrates a classic case of insufficient authorization checks within a distributed authentication system, where the system fails to properly validate the authenticity of authentication requests originating from remote MNET peers.
Organizations should implement immediate mitigations including upgrading to patched versions of Moodle where available, as well as implementing additional security controls such as network segmentation between MNET-enabled systems and critical infrastructure, and enhanced monitoring of authentication events. The vulnerability underscores the importance of proper session management and authentication token validation in distributed systems, particularly those involving federated authentication mechanisms. Security teams should also review their MNET configurations and ensure that only trusted peers have access to the authentication subsystem, while implementing additional logging and alerting mechanisms to detect potential exploitation attempts.