CVE-2019-10154 in Moodle
Summary
by MITRE
A flaw was found in Moodle before versions 3.7, 3.6.4. A web service fetching messages was not restricted to the current user's conversations.
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Analysis
by VulDB Data Team • 10/08/2023
The vulnerability identified as CVE-2019-10154 represents a critical access control flaw within the Moodle learning management system that affected versions prior to 3.7 and 3.6.4. This issue resides in the web service implementation responsible for fetching messages, where proper authorization checks were absent or insufficiently enforced. The flaw allows authenticated users to potentially access message conversations that they should not be permitted to view, creating a significant data exposure risk within educational institutions that rely on Moodle for their digital learning environments.
This vulnerability stems from a failure in the web service layer's authentication and authorization mechanisms, specifically within the message retrieval functionality. The technical implementation does not properly validate whether the requesting user has legitimate access rights to the target conversation or message thread. When users invoke the web service endpoint designed to fetch messages, the system fails to verify that the requested data belongs to the authenticated user or that the user possesses appropriate permissions to access the specific conversation. This represents a classic case of insufficient authorization checks that violates fundamental security principles of least privilege and access control enforcement.
The operational impact of this vulnerability extends beyond simple information disclosure, as it could enable unauthorized users to access sensitive communication data between students, instructors, and administrative staff. In educational environments, this could expose private academic discussions, personal communications, grade-related conversations, or confidential institutional communications. The vulnerability affects the integrity and confidentiality of user data within the Moodle platform, potentially compromising user privacy and institutional data security. Attackers could exploit this flaw to gather intelligence about users, their activities, and their relationships within the learning management system, which could be leveraged for further attacks or social engineering efforts.
Organizations using affected Moodle versions should implement immediate mitigations including upgrading to patched versions 3.7 or 3.6.4, which contain the necessary authorization fixes. Additionally, administrators should review and tighten web service access controls, implement proper user session management, and consider additional monitoring of web service usage patterns to detect potential exploitation attempts. The vulnerability aligns with CWE-284 which addresses improper access control issues, and could be categorized under ATT&CK technique T1078 for valid accounts and T1566 for credential harvesting through web service exploitation. Regular security audits of web service implementations and comprehensive access control testing should become standard practice to prevent similar vulnerabilities from emerging in the future.