CVE-2020-9386 in Mahara
Summary
by MITRE
In Mahara 18.10 before 18.10.5, 19.04 before 19.04.4, and 19.10 before 19.10.2, file metadata information is disclosed to group members in the Elasticsearch result list despite them not having access to that artefact anymore.
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Analysis
by VulDB Data Team • 03/10/2020
The vulnerability identified as CVE-2020-9386 represents a significant information disclosure flaw within the Mahara learning management system. This issue affects multiple versions including 18.10 before 18.10.5, 19.04 before 19.04.4, and 19.10 before 19.10.2, where the system fails to properly enforce access controls for file metadata within its Elasticsearch search functionality. The flaw manifests when group members can access metadata information from Elasticsearch result lists even though they no longer possess legitimate access to the underlying artefacts themselves.
The technical nature of this vulnerability stems from a breakdown in access control mechanisms within Mahara's search implementation. When the system performs Elasticsearch queries to retrieve artefact information, it appears to return metadata about files and documents that should be restricted based on user permissions. This occurs because the search results include metadata fields that are accessible through the Elasticsearch index without proper authorization checks that should validate whether the requesting user has legitimate access to the specific artefact being referenced. The vulnerability is classified under CWE-200 as an exposure of sensitive information to an unauthorized actor, specifically through improper access control in search results.
The operational impact of this vulnerability extends beyond simple information disclosure, as it potentially allows group members to gain insights into content they should not have access to. Attackers could exploit this weakness to discover the existence of specific files, document types, or content categories that are normally restricted to authorized users only. This information leakage could enable more sophisticated attacks where adversaries use the discovered metadata to target specific artefacts or to understand the structure and content of restricted repositories. The vulnerability particularly affects collaborative environments where group-based access controls are essential for maintaining content confidentiality and privacy.
Organizations using affected versions of Mahara should prioritize immediate remediation through the application of patches released in versions 18.10.5, 19.04.4, and 19.10.2 respectively. The fix likely involves implementing proper access control checks within the Elasticsearch search functionality to ensure that metadata returned in search results is filtered based on the requesting user's actual permissions. System administrators should also consider implementing additional monitoring to detect unusual search patterns that might indicate exploitation attempts. This vulnerability aligns with ATT&CK technique T1213.002 for data from other systems and represents a failure in the principle of least privilege enforcement within the application's search and retrieval mechanisms.