CVE-2011-2687 in Drupal
Summary
by MITRE
Drupal 7.x before 7.3 allows remote attackers to bypass intended node_access restrictions via vectors related to a listing that shows nodes but lacks a JOIN clause for the node table.
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Analysis
by VulDB Data Team • 01/12/2025
The vulnerability identified as CVE-2011-2687 represents a critical access control flaw in Drupal 7.x versions prior to 7.3 that enables remote attackers to circumvent node access restrictions. This issue stems from improper query construction within the content management system's database access layer, specifically affecting how node listings are generated and displayed to users. The flaw occurs in the node access control system where the database query lacks a proper JOIN clause for the node table, creating an exploitable condition that allows unauthorized users to view content they should not have access to based on their permissions.
The technical root cause of this vulnerability lies in the absence of a necessary database JOIN operation when constructing queries for node listings. In Drupal's node access system, proper access control requires joining the node table with access control tables to ensure that only authorized users can view specific content. When this JOIN clause is omitted, the query fails to properly filter results based on user permissions, leading to a situation where all nodes in the database can be exposed to any authenticated user regardless of their role or assigned permissions. This represents a fundamental breakdown in the principle of least privilege and access control enforcement within the application's architecture.
The operational impact of this vulnerability is severe as it allows attackers to bypass the intended access control mechanisms that protect sensitive content within Drupal installations. An attacker with basic user privileges can exploit this flaw to enumerate and access nodes that should be restricted to specific user roles or permissions. This could potentially expose confidential information, unpublished content, or restricted resources that are normally protected by the system's access control policies. The vulnerability affects the core node access functionality of Drupal, making it a critical concern for organizations relying on Drupal for content management and user access control.
This vulnerability maps to CWE-284, which addresses improper access control in software systems, specifically focusing on insufficient access control mechanisms. The flaw demonstrates a clear violation of access control principles where the system fails to properly enforce authorization checks during data retrieval operations. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving privilege escalation and information gathering, as attackers can leverage the flaw to access restricted content and potentially escalate their access within the system. The vulnerability also relates to TTPs associated with reconnaissance and initial access phases where attackers seek to understand system access controls and identify exploitable weaknesses.
Organizations affected by this vulnerability should immediately upgrade to Drupal 7.3 or later versions where the issue has been patched. The fix involves implementing proper database JOIN operations in the node access queries to ensure that access control checks are properly enforced. Administrators should also conduct thorough security audits of their Drupal installations to identify any other potential access control vulnerabilities and ensure that proper user role assignments and permission configurations are in place. Additionally, implementing network-level access controls and monitoring for unauthorized access attempts can help detect exploitation attempts and provide additional layers of defense. Regular security updates and vulnerability assessments should be maintained as part of the overall security posture to prevent similar issues from arising in the future.