CVE-2017-7531 in Moodle
Summary
by MITRE
In Moodle 3.3, the course overview block reveals activities in hidden courses.
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Analysis
by VulDB Data Team • 01/01/2021
The vulnerability identified as CVE-2017-7531 represents a critical information disclosure issue within the Moodle learning management system version 3.3. This flaw manifests in the course overview block functionality, which is designed to provide users with a summary view of available courses and their associated activities. The vulnerability occurs when users with appropriate permissions access the course overview block, allowing them to discover and potentially access course content that has been intentionally hidden or archived within the system. This represents a significant deviation from expected access control behavior where hidden courses should remain inaccessible to unauthorized users.
The technical root cause of this vulnerability stems from insufficient access control validation within the course overview block component. When the system generates the overview display, it fails to properly verify whether the requesting user has legitimate access rights to view the hidden course content. This flaw exists in the data retrieval and presentation logic where the system retrieves course information including activities without performing adequate permission checks. The vulnerability is classified under CWE-200, Information Disclosure, and specifically relates to insufficient access control mechanisms that allow unauthorized information exposure. The flaw demonstrates a breakdown in the principle of least privilege where users can access information beyond their designated permissions.
The operational impact of this vulnerability extends beyond simple information disclosure, creating potential security risks for educational institutions using Moodle. Attackers or malicious users with appropriate roles can exploit this vulnerability to discover hidden courses, potentially gaining access to sensitive course materials, assignments, or assessment data that should remain confidential. This exposure can lead to academic integrity issues, unauthorized access to course content, and potential data breaches. The vulnerability affects the overall security posture of Moodle installations and can be leveraged as part of broader reconnaissance activities in accordance with ATT&CK technique T1069.001 for credential access and T1566 for social engineering attacks. Organizations may inadvertently expose course materials intended for specific student populations or restricted access groups, compromising the privacy and security of educational content.
Mitigation strategies for CVE-2017-7531 should prioritize immediate patch application to the Moodle 3.3 installation, as this vulnerability was addressed in subsequent releases. Organizations should also implement additional access control measures including regular audit of course visibility settings, implementation of role-based access controls, and monitoring of user access patterns. Security administrators should review and test course access configurations to ensure that hidden courses remain properly restricted. The vulnerability highlights the importance of comprehensive security testing and validation of access control mechanisms within educational platforms. Organizations should consider implementing network segmentation, monitoring for unauthorized access attempts, and regular security assessments to prevent exploitation of similar access control vulnerabilities. Additionally, user education about proper course management and visibility settings can help prevent accidental exposure of sensitive course materials. The remediation process should include verification that the course overview block properly enforces access controls and that no unauthorized information disclosure occurs during normal system operations.