CVE-2011-4583 in Moodle
Summary
by MITRE
Moodle 2.0.x before 2.0.6 and 2.1.x before 2.1.3 displays web service tokens associated with (1) disabled services and (2) users who no longer have authorization, which allows remote authenticated users to have an unspecified impact by reading these tokens.
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Analysis
by VulDB Data Team • 02/18/2019
The vulnerability described in CVE-2011-4583 affects Moodle versions prior to 2.0.6 and 2.1.3, representing a critical security flaw in the web services authentication mechanism. This issue stems from improper token management where the system fails to properly invalidate or revoke web service tokens associated with disabled services and users who have lost their authorization privileges. The flaw exists in the core authentication and authorization framework of Moodle's web services implementation, creating a persistent security risk that can be exploited by authenticated attackers.
The technical nature of this vulnerability aligns with CWE-284, which addresses improper access control in software systems. The flaw manifests when the Moodle platform continues to display web service tokens even after the corresponding services have been disabled or the user accounts have been revoked, creating a scenario where compromised tokens can be reused by unauthorized parties. This represents a failure in the token lifecycle management process, where tokens are not properly invalidated when their associated permissions are revoked, violating fundamental principles of secure credential management.
The operational impact of this vulnerability is significant as it allows remote authenticated users to potentially gain unauthorized access to system resources through the use of stale tokens. Attackers who have previously obtained valid tokens can leverage this flaw to maintain access even after legitimate authorization has been removed, effectively bypassing access controls and creating a persistent threat vector. This vulnerability can enable privilege escalation, data exfiltration, and unauthorized system manipulation, particularly in environments where web services are used for integration with external applications or automated processes.
Organizations using affected Moodle versions should immediately implement the available patches and updates to address this vulnerability. The recommended mitigation involves upgrading to Moodle 2.0.6 or 2.1.3, which contain fixes for the token invalidation mechanism. Additionally, system administrators should conduct comprehensive audits of web service usage and token management practices, implementing regular token rotation schedules and monitoring for unauthorized access attempts. Security teams should also review and strengthen their access control policies, ensuring that token lifecycle management is properly enforced and that automated systems are configured to invalidate tokens promptly when service access is revoked or user permissions are modified, thereby reducing the attack surface and preventing exploitation of this persistent security flaw.