CVE-2015-3231 in Drupal
Summary
by MITRE
The Render cache system in Drupal 7.x before 7.38, when used to cache content by user role, allows remote authenticated users to obtain private content viewed by user 1 by reading the cache.
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Analysis
by VulDB Data Team • 05/21/2022
The vulnerability identified as CVE-2015-3231 represents a critical access control flaw within Drupal 7.x content management systems prior to version 7.38. This issue specifically affects the render cache system which is designed to improve performance by storing rendered content for later reuse. The flaw manifests when the system is configured to cache content based on user roles, creating a scenario where authenticated users can exploit the caching mechanism to access private content that should be restricted to specific user groups. The vulnerability stems from insufficient cache invalidation procedures and improper access validation during cache retrieval operations.
The technical implementation of this vulnerability exploits the interaction between Drupal's caching layer and user permission systems. When content is cached based on user roles, the system fails to properly validate whether the requesting user has legitimate access to the cached content. User 1, typically the administrative account with full system privileges, often has access to sensitive content that is cached and subsequently made available to other authenticated users who do not possess the same level of access rights. This occurs because the cache lookup mechanism does not perform adequate authorization checks before serving cached content, allowing attackers to bypass normal access controls through cache manipulation.
The operational impact of CVE-2015-3231 extends beyond simple information disclosure, as it enables authenticated attackers to potentially access sensitive administrative content, user data, and system configurations that should remain protected. This vulnerability affects organizations using Drupal 7.x installations where caching is enabled with role-based content differentiation, potentially compromising entire websites and their underlying data repositories. The risk is particularly elevated in environments where multiple users with varying permission levels exist, as the flaw can be exploited to gain unauthorized access to content that would normally be restricted to administrators or specific user groups.
Organizations affected by this vulnerability should implement immediate mitigations including upgrading to Drupal 7.38 or later versions where the issue has been resolved through improved cache validation mechanisms. Additionally, administrators should review their caching configurations to ensure that sensitive content is not cached in ways that could expose it to unauthorized users. The fix addresses the underlying CWE-284 access control weakness by implementing proper authorization checks during cache retrieval operations, preventing cached content from being served to users who lack appropriate permissions. Security teams should also consider implementing network-level monitoring to detect unusual cache access patterns that might indicate exploitation attempts, aligning with ATT&CK technique T1078 for legitimate credentials and T1566 for credential harvesting through cache manipulation.