CVE-2012-2367 in Moodle
Summary
by MITRE
Moodle 1.9.x before 1.9.18, 2.0.x before 2.0.9, 2.1.x before 2.1.6, and 2.2.x before 2.2.3 allows remote authenticated users to bypass the moodle/calendar:manageownentries capability requirement and add a calendar entry via a New Entry action.
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Analysis
by VulDB Data Team • 12/06/2021
The vulnerability described in CVE-2012-2367 represents a significant authorization bypass flaw within the Moodle learning management system that affects multiple version branches including 1.9.x through 1.9.17, 2.0.x through 2.0.8, 2.1.x through 2.1.5, and 2.2.x through 2.2.2. This issue stems from insufficient capability checks within the calendar management functionality, specifically targeting the moodle/calendar:manageownentries permission requirement. The flaw allows authenticated users to circumvent the intended access controls and perform calendar entry creation actions without possessing the proper authorization level. This vulnerability operates at the application level and demonstrates a critical weakness in Moodle's permission architecture where the system fails to properly validate user capabilities before executing calendar-related operations. The vulnerability is classified under CWE-285 which specifically addresses insufficient authorization checks, making it a direct violation of proper access control mechanisms.
The technical implementation of this vulnerability occurs within the calendar entry creation process where the application does not adequately verify whether the authenticated user possesses the required moodle/calendar:manageownentries capability before allowing the New Entry action to proceed. This represents a classic case of inadequate input validation and privilege escalation where the system assumes that any authenticated user can perform calendar management tasks without proper authorization checks. The flaw exists in the core calendar module functionality and affects the integrity of the system's access control model by allowing unauthorized users to create calendar entries that should only be permitted for users with specific privileges. The vulnerability is particularly concerning because it operates within a legitimate user session, making it difficult to detect and exploit through traditional network-based security measures. This weakness enables attackers to manipulate the calendar system and potentially create entries that could be used for further exploitation or to disrupt normal system operations.
The operational impact of this vulnerability extends beyond simple unauthorized calendar entries as it represents a fundamental breakdown in Moodle's security model that could enable more sophisticated attacks. An attacker with a valid user account could leverage this vulnerability to create calendar entries that might contain malicious links or be used to facilitate social engineering attacks against other users. The ability to bypass capability checks in this manner could potentially allow for the creation of calendar entries that appear to originate from authorized users, thereby undermining trust in the system's integrity. From a compliance perspective, this vulnerability could violate security standards such as those outlined in the NIST Cybersecurity Framework and could compromise the organization's ability to maintain proper audit trails and access control policies. The vulnerability also affects the availability and integrity of calendar data, as unauthorized entries could disrupt normal scheduling operations or be used to hide malicious activities within the system.
Mitigation strategies for this vulnerability should focus on immediate patching of affected Moodle installations to the latest available versions that contain the necessary security fixes. Organizations should implement comprehensive security monitoring to detect unauthorized calendar activities and establish proper access control reviews to ensure that users only possess the minimum necessary privileges. The fix typically involves implementing proper capability checks within the calendar entry creation process to validate that users possess the required moodle/calendar:manageownentries permission before allowing calendar operations to proceed. Security teams should also consider implementing network-based controls to monitor for unusual calendar activity patterns and establish proper user access reviews to ensure that calendar management permissions are appropriately assigned. This vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and privilege escalation, as it allows attackers to perform unauthorized actions using legitimate user credentials. Organizations should also implement proper security awareness training to help users understand the importance of maintaining proper access controls and recognizing potential signs of calendar-based attacks. The remediation process should include thorough testing to ensure that the patched version functions correctly while maintaining all necessary calendar functionality for authorized users.