CVE-2012-4407 in Moodle
Summary
by MITRE
lib/filelib.php in Moodle 2.1.x before 2.1.8, 2.2.x before 2.2.5, and 2.3.x before 2.3.2 does not properly check the publication state of blog files, which allows remote attackers to obtain sensitive information by reading a blog entry that references a non-public file.
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Analysis
by VulDB Data Team • 12/14/2021
The vulnerability described in CVE-2012-4407 represents a critical access control flaw within the Moodle learning management system that affects multiple versions including 2.1.x before 2.1.8, 2.2.x before 2.2.5, and 2.3.x before 2.3.2. This issue stems from inadequate validation of file publication states within the blog functionality, creating a path for unauthorized information disclosure. The flaw specifically resides in the lib/filelib.php component which handles file operations and access controls. Attackers can exploit this vulnerability by crafting blog entries that reference non-public files, thereby bypassing the intended access restrictions that should prevent unauthorized users from accessing sensitive content.
The technical implementation of this vulnerability demonstrates a classic improper access control scenario where the system fails to verify whether a user has appropriate permissions to access specific files referenced in blog posts. When a blog entry contains references to files that should remain private or restricted to certain user roles, the system does not properly validate the publication state of these files before allowing access. This misconfiguration allows remote attackers to circumvent the normal permission checks that should occur when users attempt to view blog entries containing file references. The vulnerability operates at the application layer and requires no special privileges to exploit, making it particularly dangerous as it can be leveraged by anyone with access to the affected Moodle instance.
The operational impact of CVE-2012-4407 extends beyond simple information disclosure, potentially exposing sensitive educational content, personal data, or institutional materials that should remain confidential. In educational environments, this vulnerability could lead to exposure of student assignments, graded work, private communications, or administrative documents that are improperly marked as public within blog entries. The attack vector is particularly concerning because it requires minimal technical expertise and can be executed remotely, allowing attackers to systematically discover and access restricted files through blog entries. This type of vulnerability directly violates security principles outlined in the OWASP Top Ten, specifically addressing the issue of insufficient access control mechanisms that should protect sensitive data within web applications.
The exploitation of this vulnerability aligns with techniques described in the ATT&CK framework under the initial access and privilege escalation domains, where attackers can leverage insecure file handling to gain unauthorized access to restricted resources. From a CWE perspective, this represents a variant of CWE-284: Improper Access Control, specifically manifesting as inadequate protection of file access controls within a content management system. The vulnerability demonstrates poor input validation and insufficient authorization checks, creating a pathway for attackers to bypass the intended security boundaries that separate public and private content within the Moodle platform. Organizations using affected Moodle versions face significant risk of data breaches and potential compliance violations, particularly in regulated educational environments where student privacy and data protection are paramount considerations.
The recommended mitigation strategy involves immediate upgrade to patched versions of Moodle that address this access control flaw, specifically versions 2.1.8, 2.2.5, and 2.3.2 or later. Administrators should also review and audit existing blog entries to ensure no sensitive files are improperly referenced, implement additional monitoring of file access patterns, and consider implementing network-level restrictions to limit access to potentially vulnerable components. Security hardening measures including regular security audits, proper file permission configurations, and comprehensive access control reviews should be implemented to prevent similar vulnerabilities from emerging in other system components. Organizations should also establish processes for regularly updating and patching their learning management systems to maintain security posture against known vulnerabilities.