CVE-2015-5515 in Views Bulk Operations
Summary
by MITRE
The Views Bulk Operations (VBO) module 6.x-1.x and 7.x-3.x before 7.x-3.3 for Drupal, when the bulk operation for changing Roles is enabled, allows remote authenticated users to edit user accounts and add arbitrary roles to the accounts by leveraging access to a user account listing view with VBO enabled.
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Analysis
by VulDB Data Team • 10/18/2017
The vulnerability identified as CVE-2015-5515 affects the Views Bulk Operations module in Drupal versions 6.x-1.x and 7.x-3.x prior to 7.x-3.3. This security flaw represents a critical access control weakness that enables authenticated attackers to manipulate user account permissions through a specific configuration involving user account listing views with VBO functionality enabled. The vulnerability stems from insufficient authorization checks within the module's bulk operation processing mechanism, specifically when handling role modification operations. Attackers can exploit this by accessing a user account listing view that has VBO enabled and then leveraging their authenticated status to perform unauthorized role assignments to other user accounts.
The technical implementation of this vulnerability occurs when the Views Bulk Operations module processes bulk operations without properly validating whether the authenticated user possesses sufficient privileges to modify the target user accounts. This flaw operates under CWE-285, which addresses insufficient authorization checks, and specifically manifests as an improper access control mechanism. The vulnerability is particularly dangerous because it allows attackers to escalate privileges by adding arbitrary roles to user accounts, potentially granting them administrative capabilities or access to restricted resources. The attack vector requires only that the attacker have access to a user listing view with VBO enabled, which is often a standard feature in Drupal administrative interfaces.
The operational impact of CVE-2015-5515 extends beyond simple privilege escalation, as it can enable attackers to gain persistent access to systems by adding themselves to administrative roles or creating accounts with elevated permissions. This vulnerability directly violates the principle of least privilege and can be leveraged as part of a broader attack chain in accordance with ATT&CK technique T1078 for valid accounts and T1548 for privilege escalation. The affected systems typically include Drupal installations where administrators have configured user listing views with bulk operation capabilities, making this vulnerability particularly prevalent in content management systems that utilize these common administrative features. Organizations may experience unauthorized access to sensitive data, system compromise, or complete administrative control when this vulnerability is exploited.
Mitigation strategies for CVE-2015-5515 require immediate patching of the Views Bulk Operations module to version 7.x-3.3 or later, which includes proper authorization checks for bulk operations. System administrators should also review and restrict access to user listing views with VBO enabled, implementing appropriate role-based access controls to ensure that only authorized personnel can perform bulk operations. Additional security measures include monitoring for unauthorized bulk operations, implementing network segmentation to limit access to administrative interfaces, and conducting regular security audits of Drupal modules and their configurations. Organizations should also consider implementing web application firewalls to detect and block suspicious bulk operation requests, and establish incident response procedures specifically addressing privilege escalation attempts through bulk operations. The vulnerability highlights the importance of proper input validation and authorization checking in web applications, particularly those handling user account management functions.