CVE-2012-3391 in Moodle
Summary
by MITRE
mod/forum/rsslib.php in Moodle 2.1.x before 2.1.7 and 2.2.x before 2.2.4 does not properly implement the requirement for posting before reading a Q&A forum, which allows remote authenticated users to bypass intended access restrictions by leveraging the student role and reading the RSS feed for a forum.
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Analysis
by VulDB Data Team • 12/06/2021
The vulnerability described in CVE-2012-3391 affects Moodle learning management systems version 2.1.x prior to 2.1.7 and 2.2.x prior to 2.2.4, specifically within the mod/forum/rsslib.php component. This security flaw represents a significant access control bypass issue that undermines the intended forum functionality designed for Q&A discussions. The vulnerability stems from improper implementation of the forum posting requirements that are meant to ensure students cannot view forum content until they have first posted their own contributions.
The technical implementation flaw occurs in the RSS feed generation logic where the system fails to validate whether users have met the prerequisite of posting before reading Q&A forum content. This misconfiguration allows authenticated users with the student role to circumvent the intended access restrictions by directly accessing the RSS feed endpoint. The vulnerability exploits the fundamental design principle that Q&A forums should require initial participation before allowing content consumption, a common security pattern implemented in educational platforms to encourage student engagement and prevent information leakage.
From an operational perspective, this vulnerability enables unauthorized information disclosure and potential abuse of educational content within Moodle environments. Remote authenticated users can access forum discussions, responses, and potentially sensitive information without fulfilling the required posting conditions. The impact extends beyond simple information disclosure as it undermines the pedagogical integrity of Q&A forums where the posting requirement is designed to promote active learning and peer interaction. This could lead to grade manipulation, cheating opportunities, or exposure of discussion content that was intended to remain private until student participation occurred.
The vulnerability aligns with CWE-668, which describes "Exposure of Resource to Wrong Sphere," and represents a clear case of improper access control implementation. From an ATT&CK framework perspective, this issue maps to T1078.004, "Valid Accounts: Cloud Accounts," and T1566.001, "Phishing: Spearphishing Attachment," as it enables attackers to gain access to educational content that should remain restricted. Organizations using affected Moodle versions face potential compliance risks, particularly in environments subject to educational privacy regulations such as FERPA or GDPR, where unauthorized access to student discussions could constitute a privacy violation.
Mitigation strategies should focus on immediate patching of affected Moodle installations to versions 2.1.7 or 2.2.4 and subsequent releases. Administrators should also implement additional monitoring of RSS feed access patterns and consider role-based access controls that further restrict forum access. The vulnerability demonstrates the importance of thorough security testing for educational platforms and highlights the need for proper input validation and access control mechanisms in web applications. Organizations should conduct comprehensive security assessments of their Moodle deployments to identify similar access control issues and ensure proper implementation of forum posting requirements across all course content types.