CVE-2021-40692 in Moodle
Summary
by MITRE • 09/29/2022
Insufficient capability checks made it possible for teachers to download users outside of their courses.
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Analysis
by VulDB Data Team • 10/25/2022
This vulnerability exists within educational platform systems where access controls fail to properly verify user capabilities before allowing data export operations. The flaw stems from inadequate authorization checks that permit teachers to bypass normal course boundaries and access user information from other courses they should not be authorized to view. Such insufficient capability checks represent a direct violation of the principle of least privilege and create dangerous escalation paths for unauthorized data access.
The technical implementation of this vulnerability typically involves weak validation mechanisms within the platform's user management and data export functions. When teachers attempt to download user information, the system fails to properly authenticate their permissions against the specific course contexts they are authorized to access. This allows malicious or unauthorized teachers to enumerate and extract data from users in courses outside their designated teaching scope, potentially exposing sensitive student information, grades, and personal details across multiple academic contexts.
The operational impact of this vulnerability extends beyond simple data exposure to encompass serious privacy violations and potential compliance breaches. Educational institutions must maintain strict data governance policies to protect student privacy, and this vulnerability undermines those protections by enabling unauthorized cross-course data access. The risk is particularly severe when considering that teachers may have varying levels of access rights, and the vulnerability allows for broad data exfiltration without proper authorization boundaries. This creates opportunities for data misuse, identity theft, and violation of educational privacy regulations such as FERPA in the united states or similar data protection laws globally.
Mitigation strategies should focus on implementing robust access control mechanisms that enforce strict capability checks before any data export operations are permitted. The system must validate that teachers can only access user information within courses where they hold legitimate teaching permissions, using proper authorization frameworks that align with established security standards. Organizations should implement comprehensive role-based access controls, regular security audits of access permissions, and continuous monitoring of data export activities. Additionally, the implementation of automated alerting systems for unauthorized access attempts and regular penetration testing can help identify and remediate similar capability check failures. This vulnerability aligns with CWE-284 which addresses improper access control, and represents a clear violation of ATT&CK technique T1078 which covers valid accounts and privilege escalation.