CVE-2015-5506 in Apache Solr Real-Time Module
Summary
by MITRE
The Apache Solr Real-Time module 7.x-1.x before 7.x-1.2 for Drupal does not check the status of an entity when indexing, which allows remote attackers to obtain information about unpublished content via a search.
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Analysis
by VulDB Data Team • 03/10/2018
The Apache Solr Real-Time module for Drupal presents a significant information disclosure vulnerability that stems from inadequate access control mechanisms during the indexing process. This vulnerability affects versions 7.x-1.x prior to 7.x-1.2 and specifically targets the module's failure to validate entity status before adding content to the search index. The flaw exists within the module's design philosophy where it assumes that all entities processed for indexing are publicly accessible, thereby bypassing Drupal's inherent content access control systems. This represents a critical oversight in the module's architecture, as it fails to integrate with Drupal's permission model that typically prevents unauthorized access to unpublished content.
The technical implementation of this vulnerability exploits the module's real-time indexing functionality, which automatically processes and indexes content as it is created or modified within the Drupal system. When the module performs indexing operations, it does not query the Drupal access control system to verify whether the entity being indexed should be publicly accessible. This means that unpublished content, which should normally be restricted to authorized users or administrators, gets included in the search index and becomes discoverable through search queries. The vulnerability operates at the intersection of content management and search indexing, where the module's indexing process lacks proper authorization checks that should occur before content is made searchable.
From an operational perspective, this vulnerability creates a serious risk for organizations relying on Drupal with Solr integration for content management. Remote attackers can exploit this weakness to gain unauthorized access to unpublished content, potentially including sensitive information, draft documents, or content that has not yet been approved for public viewing. The impact extends beyond simple information disclosure as it undermines the fundamental security model of content management systems, allowing attackers to bypass the normal workflow controls that prevent unauthorized access to content. This vulnerability particularly affects organizations that rely heavily on Drupal's content staging and approval processes, where unpublished content represents a significant security risk if exposed to unauthorized parties.
The vulnerability aligns with several cybersecurity frameworks and standards, including CWE-200, which addresses "Information Exposure," and represents a clear violation of the principle of least privilege in access control. From an ATT&CK framework perspective, this vulnerability maps to T1068, "Exploitation for Privilege Escalation," and T1566, "Phishing," as attackers could potentially use this information disclosure to craft more targeted attacks. The module's failure to implement proper access validation during indexing operations directly contradicts industry best practices for secure content management systems and demonstrates a lack of security-by-design principles in the module's development. Organizations should consider implementing immediate mitigations including upgrading to the patched version 7.x-1.2 or applying custom patches that enforce proper access control checks before indexing content.
The remediation strategy should focus on ensuring that all indexing operations validate entity access permissions against Drupal's access control system before content is added to the search index. This requires modifications to the module's core indexing logic to incorporate proper access checks, potentially through the use of Drupal's node_access() functions or similar permission validation mechanisms. Organizations should also consider implementing additional monitoring and logging of indexing operations to detect potential unauthorized access attempts. The vulnerability highlights the importance of security testing during the development lifecycle, particularly for modules that interact with core system functionality like content indexing and access control. Regular security audits of third-party modules should be conducted to identify similar access control weaknesses that could compromise system integrity and data confidentiality.