CVE-2017-12157 in Moodle
Summary
by MITRE
In Moodle 3.x, various course reports allow teachers to view details about users in the groups they can't access.
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Analysis
by VulDB Data Team • 12/29/2022
The vulnerability identified as CVE-2017-12157 affects Moodle version 3.x and represents a significant access control flaw that undermines the platform's security model. This issue specifically impacts course reporting functionality where teachers can potentially access user details and information about students within groups they are not authorized to view. The flaw exists within the course reporting mechanisms that fail to properly enforce group membership restrictions, creating an unintended information disclosure channel that violates fundamental security principles of least privilege and access control.
This vulnerability stems from inadequate authorization checks within the course reporting components of Moodle's architecture. When teachers generate various course reports, the system does not properly validate whether the reporting user has legitimate access rights to the groups and users referenced in those reports. The technical implementation fails to cross-reference user permissions against group memberships, allowing unauthorized access to sensitive educational data. This represents a classic privilege escalation vulnerability that can be categorized under CWE-285, which deals with improper authorization in software systems. The flaw essentially allows teachers to bypass normal access controls that should restrict them to only viewing information about students within their own groups or courses they are directly teaching.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates potential risks for student privacy and educational data protection. Teachers could gain access to personal information, academic performance data, and other sensitive details about students in groups they should not have access to, potentially including students from other courses or departments. This could lead to unauthorized surveillance, privacy violations, and breaches of educational data protection regulations such as FERPA in the united states or GDPR in europe. The vulnerability affects the integrity of the entire Moodle ecosystem by undermining trust in the access control mechanisms that are fundamental to maintaining secure educational environments. Attackers could exploit this by simply navigating to specific reporting pages and generating reports that reveal unauthorized information about students in other groups.
Mitigation strategies for this vulnerability should focus on implementing robust access control validation within all course reporting functions. Organizations should ensure that Moodle is updated to versions that address this specific flaw, as the issue was resolved in subsequent releases through enhanced permission checking mechanisms. Administrators should conduct regular audits of user permissions and group memberships to identify any potential unauthorized access patterns. The implementation of proper role-based access controls and regular security testing of reporting functions should be mandatory. Additionally, organizations should consider implementing network-level monitoring to detect unusual reporting activity that might indicate exploitation attempts. This vulnerability aligns with ATT&CK technique T1068, which involves the use of legitimate credentials to gain access to restricted systems, as it exploits the legitimate teacher role to access unauthorized information through flawed permission validation mechanisms.