CVE-2011-4297 in Moodle
Summary
by MITRE
comment/lib.php in Moodle 2.0.x before 2.0.4 and 2.1.x before 2.1.1 does not properly restrict comment capabilities, which allows remote attackers to post a comment by leveraging the guest role and operating on a front-page activity.
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Analysis
by VulDB Data Team • 12/06/2021
The vulnerability identified as CVE-2011-4297 affects Moodle learning management systems version 2.0.x before 2.0.4 and 2.1.x before 2.1.1, specifically within the comment/lib.php component. This flaw represents a critical access control weakness that undermines the platform's security model by allowing unauthorized users to post comments on front-page activities through the guest role. The issue stems from insufficient validation of user permissions and role-based access controls within the comment submission mechanism, creating a pathway for malicious actors to bypass normal authentication requirements.
The technical implementation of this vulnerability resides in the comment/lib.php file where the system fails to properly enforce authorization checks when processing comment submissions. When a guest user attempts to post a comment on a front-page activity, the application does not adequately verify whether the guest role should be permitted to perform such actions. This misconfiguration allows attackers to exploit the guest user account, which typically has limited privileges, to execute comment operations that should be restricted to authenticated users with appropriate permissions. The flaw operates at the application logic level, specifically in the comment submission workflow where role-based access controls are improperly enforced.
The operational impact of this vulnerability extends beyond simple comment posting capabilities and represents a significant security risk for educational institutions using affected Moodle versions. Attackers can leverage this vulnerability to post malicious content, spam forums, or potentially disrupt the educational environment by injecting inappropriate comments into public-facing activities. The vulnerability is particularly concerning because it affects front-page activities, which are typically accessible to all users including unauthenticated guests, making the attack surface broad and easily exploitable. This weakness could enable social engineering attacks, content poisoning, or reputational damage to institutions relying on Moodle for their learning management infrastructure.
Organizations affected by this vulnerability should immediately upgrade to Moodle versions 2.0.4 or 2.1.1, which contain the necessary patches to address the comment capability restrictions. The fix involves implementing proper role-based access control checks within the comment/lib.php file to ensure that only users with appropriate permissions can submit comments on specific activities. Security administrators should also conduct thorough reviews of their Moodle configurations to verify that guest user privileges are appropriately restricted and that comment submission mechanisms are properly secured. This vulnerability aligns with CWE-284, which addresses improper access control, and could be exploited as part of broader attack patterns categorized under the ATT&CK technique of privilege escalation through unsecured web applications. Organizations should implement additional monitoring for unusual comment activity and consider implementing web application firewalls to detect and block exploitation attempts targeting this specific vulnerability.