CVE-2013-4477 in Grizzly
Summary
by MITRE
The LDAP backend in OpenStack Identity (Keystone) Grizzly and Havana, when removing a role on a tenant for a user who does not have that role, adds the role to the user, which allows local users to gain privileges.
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Analysis
by VulDB Data Team • 12/25/2024
The vulnerability identified as CVE-2013-4477 resides within the Lightweight Directory Access Protocol backend implementation of OpenStack Identity service known as Keystone. This flaw affects versions Grizzly and Havana of the OpenStack platform, where the role management functionality exhibits incorrect behavior when processing role removal operations. The issue manifests specifically when attempting to remove a role from a user within a tenant context, but only for users who do not actually possess that role. The improper implementation causes the system to inadvertently grant the requested role to the user instead of simply ignoring the operation or returning an appropriate error condition.
The technical root cause of this vulnerability stems from a flawed access control mechanism within Keystone's LDAP backend component. When the system processes a role removal request, it fails to properly validate whether the target user actually holds the specified role before executing any modifications. This validation gap creates a logical inconsistency where the system's behavior contradicts its intended operation. According to CWE-284 access control flaws, this represents a privilege escalation vulnerability where unauthorized modifications to user permissions occur due to insufficient validation of user entitlements. The flaw operates at the authorization level, specifically within the role management subsystem where proper access control checks are missing or incorrectly implemented.
The operational impact of this vulnerability is significant for cloud environments relying on OpenStack Keystone for identity management. Local users who can interact with the Keystone service can exploit this weakness to gain unauthorized privileges within tenant contexts. This creates a scenario where malicious actors can escalate their privileges by attempting to remove roles from users who don't possess them, effectively granting themselves those roles through the system's faulty logic. The vulnerability essentially allows for privilege escalation attacks that bypass normal access control mechanisms, potentially enabling attackers to gain elevated permissions within the cloud infrastructure. From an ATT&CK perspective, this maps to privilege escalation techniques where adversaries manipulate access control systems to gain higher-level permissions.
The security implications extend beyond simple privilege escalation to encompass potential data exposure and system compromise within OpenStack deployments. Organizations using affected Keystone versions face the risk of unauthorized access to tenant resources, as the vulnerability allows attackers to effectively bypass role-based access controls. This creates a persistent threat vector that could enable attackers to move laterally within cloud environments, access sensitive tenant data, and potentially compromise the broader cloud infrastructure. The vulnerability's impact is particularly concerning in multi-tenant environments where proper isolation between users and tenants is critical for maintaining security boundaries.
Mitigation strategies for CVE-2013-4477 involve immediate patching of affected OpenStack Keystone installations to versions that properly implement role validation logic. Organizations should also implement additional monitoring and logging of role management operations to detect anomalous behavior patterns that might indicate exploitation attempts. Security teams should review and validate existing access control policies to ensure proper enforcement of role-based permissions. The fix requires proper implementation of role existence checks before any modification operations, ensuring that role removal attempts only succeed when the target role actually exists for the user. Additionally, organizations should consider implementing network segmentation and access controls to limit exposure of Keystone services to only authorized administrative systems, reducing the attack surface for potential exploitation.