A flaw was found in Moodle. This authentication bypass vulnerability allows suspended users to authenticate through the Learning Tools Interoperability (LTI) Provider. The issue arises from the LTI authentication handlers failing to enforce the users suspension status, enabling unauthorized access to the system. This can lead to information disclosure or other unauthorized actions by users who should be restricted.
Weakness
The product does not handle or incorrectly handles when it has insufficient privileges to access resources or functionality as specified by their permissions. This may cause it to follow unexpected code paths that may leave the product in an invalid state.
Potential Mitigations
- Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
- Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.