CVE-2023-29057 in XClarity Controller
Summary
by MITRE • 04/29/2023
A valid XCC user's local account permissions overrides their active directory permissions under specific configurations. This could lead to a privilege escalation. To be vulnerable, LDAP must be configured for authentication/authorization and logins configured as “Local First, then LDAP”.
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Analysis
by VulDB Data Team • 05/24/2023
This vulnerability exists within XCC user authentication systems where local account permissions can override Active Directory permissions under specific configuration conditions. The flaw represents a classic privilege escalation vector that exploits the order of authentication attempts within the system's login process. When LDAP authentication is configured alongside local authentication, and the system is set to prioritize local accounts before attempting LDAP authentication, users authenticated through the local account mechanism can retain elevated local permissions even when their Active Directory credentials would normally grant them lower privileges. This creates a scenario where an attacker who gains access to a valid local account can potentially maintain elevated privileges beyond what their Active Directory permissions should allow. The vulnerability specifically impacts systems configured with "Local First, then LDAP" login precedence, which is a common configuration pattern in enterprise environments that rely on both local and domain authentication mechanisms. This configuration pattern is particularly dangerous because it allows local account credentials to bypass the normal Active Directory permission hierarchy that would typically enforce proper access controls and privilege boundaries.
The technical implementation of this vulnerability stems from improper authentication precedence handling within the XCC system's user permission resolution logic. When a user authenticates through a local account that exists in both the local system and Active Directory, the system fails to properly merge or override the permission sets according to established security principles. This creates a situation where local account permissions, which may be more permissive than the corresponding Active Directory permissions, take precedence over the domain-based access controls. The vulnerability operates at the intersection of authentication and authorization mechanisms, where the order of authentication attempts directly influences the final permission set assigned to the user. This behavior violates fundamental security principles of least privilege and privilege separation, as demonstrated by the CWE-284 access control weakness classification. The system should enforce a clear hierarchy of authentication sources where domain-based permissions should take precedence over local permissions, but instead allows local credentials to override domain-based access controls.
The operational impact of this vulnerability is significant for enterprise environments that rely on hybrid authentication models. Organizations using "Local First, then LDAP" configurations are particularly at risk because they create a backdoor for privilege escalation attacks. An attacker who compromises a local account can potentially maintain elevated access rights even when their Active Directory credentials would normally restrict their privileges to a lower level. This could enable lateral movement within the network, access to sensitive systems, and potential data exfiltration. The vulnerability is especially concerning in environments where local accounts are used for administrative access or where local permissions are more permissive than domain-based permissions. Security teams may not immediately detect this privilege escalation because the behavior appears normal from the user perspective, as the local account authentication succeeds and provides the elevated local permissions. This vulnerability directly aligns with the ATT&CK technique T1078 legitimate credentials, where attackers can leverage legitimate local accounts to maintain persistent access and escalate privileges beyond normal operational boundaries.
Mitigation strategies for this vulnerability require careful configuration review and implementation of proper authentication precedence controls. Organizations should avoid "Local First, then LDAP" configurations unless absolutely necessary, and when such configurations are required, they should implement strict permission merging policies that ensure Active Directory permissions take precedence over local permissions. The system configuration should enforce that domain-based authentication results override local account permissions, regardless of authentication order. Security administrators should implement regular audits of local account permissions to ensure they align with the intended access control policies. Additionally, organizations should consider implementing multi-factor authentication for local accounts and establish monitoring for unusual privilege escalation patterns. The recommended approach aligns with the principle of least privilege as outlined in security frameworks and emphasizes the importance of proper authentication hierarchy management. System administrators should also consider implementing automated tools to detect and alert on configuration changes that could introduce this vulnerability, particularly around authentication precedence settings. Regular security assessments should include verification of authentication order configurations and permission resolution behaviors to prevent unauthorized privilege escalation through this mechanism.