CVE-2016-0724 in Moodle
Summary
by MITRE
The (1) core_enrol_get_course_enrolment_methods and (2) enrol_self_get_instance_info web services in Moodle through 2.6.11, 2.7.x before 2.7.12, 2.8.x before 2.8.10, 2.9.x before 2.9.4, and 3.0.x before 3.0.2 do not consider the moodle/course:viewhiddencourses capability, which allows remote authenticated users to obtain sensitive information via a web-service request.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 07/08/2022
The vulnerability identified as CVE-2016-0724 affects Moodle learning management systems across multiple versions including 2.6.11 and earlier, 2.7.x through 2.7.11, 2.8.x through 2.8.9, 2.9.x through 2.9.3, and 3.0.x through 3.0.1. This security flaw resides in two specific web services: core_enrol_get_course_enrolment_methods and enrol_self_get_instance_info which are designed to provide course enrollment information to authenticated users. The vulnerability stems from the failure of these web services to properly validate user permissions when accessing course enrollment data, creating an information disclosure risk that impacts the confidentiality of course enrollment details.
The technical root cause of this vulnerability lies in the improper implementation of access control checks within the Moodle web service framework. When authenticated users make requests to these specific web services, the system fails to verify whether the requesting user possesses the required capability moodle/course:viewhiddencourses before returning enrollment information. This capability should be checked to ensure that users can only access enrollment details for courses they are authorized to view, including hidden courses. The absence of this capability check allows malicious users to bypass normal access controls and retrieve sensitive enrollment data that would normally be restricted to authorized personnel only.
The operational impact of this vulnerability extends beyond simple information disclosure as it creates opportunities for unauthorized users to gather intelligence about course structures, enrollment patterns, and potentially identify vulnerable course configurations. Attackers could leverage this weakness to map course enrollment relationships, identify popular or sensitive courses, and potentially use this information for further exploitation attempts. The vulnerability affects remote authenticated users, meaning that any user with valid login credentials can exploit this flaw without requiring special privileges or physical access to the system. This makes the attack surface particularly broad and concerning for educational institutions relying on Moodle for their learning management needs.
This vulnerability aligns with CWE-200, which describes improper output neutralization for logs, and represents a classic case of insufficient access control where the system fails to properly enforce authorization checks. The ATT&CK framework categorizes this as a privilege escalation technique through information gathering, where adversaries can use the disclosed information to plan more sophisticated attacks against the system. The flaw also relates to CWE-501, which addresses trust violations in web services, since the system fails to properly validate the requesting user's authorization level before returning sensitive data.
Organizations affected by this vulnerability should immediately apply the patches released by Moodle for their specific version ranges, particularly focusing on upgrading to versions 2.7.12, 2.8.10, 2.9.4, and 3.0.2 or later. System administrators should also implement additional monitoring to detect unusual patterns in web service usage that might indicate exploitation attempts. The mitigation strategy should include verifying that all web service calls properly validate user capabilities before returning sensitive data, and implementing principle of least privilege enforcement for all web service endpoints. Regular security assessments should be conducted to ensure that no other similar access control bypass vulnerabilities exist within the system's web service framework.