CVE-2011-4961 in SilverStripe
Summary
by MITRE
SilverStripe 2.3.x before 2.3.12 and 2.4.x before 2.4.6 allows remote authenticated users with the EDIT_PERMISSIONS permission to gain administrator privileges via a TreeMultiselectField that includes admin groups when adding a user to the selected groups.
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Analysis
by VulDB Data Team • 12/13/2021
This vulnerability exists in SilverStripe content management systems version 2.3.x prior to 2.3.12 and 2.4.x prior to 2.4.6, representing a critical privilege escalation flaw that undermines the application's access control mechanisms. The vulnerability specifically affects users who possess the EDIT_PERMISSIONS permission level but should not have administrative capabilities. The flaw manifests through a TreeMultiselectField component that is used during user management operations, where authenticated users can manipulate group assignments to include administrative groups. This represents a classic case of insufficient authorization checking where the application fails to properly validate whether a user has the necessary privileges to assign administrative roles to other users.
The technical implementation of this vulnerability exploits a design flaw in the permission validation logic within SilverStripe's user management interface. When an authenticated user with EDIT_PERMISSIONS attempts to add another user to groups via the TreeMultiselectField, the system does not properly verify whether the acting user has elevated privileges to assign administrative group memberships. This allows the user to select administrative groups from the multiselect field and effectively grant themselves or others administrator privileges without proper authorization. The vulnerability is particularly dangerous because it operates within the legitimate user management workflow, making it difficult to detect through standard security monitoring mechanisms. This flaw falls under CWE-284 which describes improper access control, specifically focusing on inadequate authorization checks during privilege assignment operations.
The operational impact of this vulnerability is severe as it allows attackers to escalate their privileges from standard user level to full administrator access without requiring additional authentication credentials. This means that any authenticated user with EDIT_PERMISSIONS can potentially compromise the entire system by granting themselves or other users administrative capabilities. The vulnerability can be exploited repeatedly and may persist across system sessions, creating a long-term security risk. Organizations using affected SilverStripe versions face potential data breaches, unauthorized system modifications, and complete loss of administrative control over their web applications. The attack vector is relatively simple and can be executed through standard web browser interfaces, making it accessible to attackers with minimal technical expertise beyond basic authentication access.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected SilverStripe installations to versions 2.3.12 or 2.4.6 and later. Organizations should also implement additional access controls such as restricting the ability to modify user groups to only users with explicit administrative permissions. Network segmentation and monitoring should be enhanced to detect unusual group assignment patterns. Security teams should conduct comprehensive audits of user permissions and group memberships to identify any unauthorized privilege escalations that may have already occurred. Implementing principle of least privilege configurations where users have minimal necessary permissions can help reduce the impact if similar vulnerabilities are discovered in the future. This vulnerability demonstrates the critical importance of proper authorization checks in multi-tiered applications and aligns with ATT&CK technique T1078 which covers valid accounts and privilege escalation through unauthorized access to administrative functions. Regular security assessments and code reviews focusing on permission validation logic are essential for preventing similar issues in other applications and systems.