CVE-2017-8038 in Cloud Foundry
Summary
by MITRE
In Cloud Foundry Foundation Credhub-release version 1.1.0, access control lists (ACLs) enforce whether an authenticated user can perform an operation on a credential. For installations using ACLs, the ACL was bypassed for the CredHub interpolate endpoint, allowing authenticated applications to view any credential within the CredHub installation.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 12/10/2019
The vulnerability identified as CVE-2017-8038 affects Cloud Foundry Foundation Credhub-release version 1.1.0 and represents a critical access control flaw that undermines the security architecture of the credential management system. This issue specifically targets the implementation of access control lists within Credhub, which are designed to enforce strict permissions for authenticated users when performing operations on sensitive credentials. The flaw manifests in the CredHub interpolate endpoint where the access control list mechanism fails to properly validate user permissions, creating a bypass condition that allows unauthorized access to credential data.
The technical implementation of this vulnerability stems from an improper validation of authentication and authorization states within the interpolate endpoint functionality. When applications make requests to this endpoint, the system should verify that the requesting entity has appropriate permissions to access the target credential, but this validation process is circumvented. This bypass effectively allows any authenticated application to retrieve credentials that would normally be restricted based on the configured access control lists, fundamentally undermining the principle of least privilege that governs credential security. The flaw operates at the application layer and affects the integrity of the entire credential management infrastructure.
The operational impact of this vulnerability is severe and far-reaching for organizations utilizing Cloud Foundry environments with Credhub deployments. An attacker who gains access to any authenticated application within the system can leverage this bypass to extract sensitive information from the entire credential store, potentially including database passwords, API keys, encryption certificates, and other critical secrets. This represents a complete breakdown of the access control model and could lead to unauthorized data access, privilege escalation, and potential system compromise. The vulnerability affects all installations using ACLs, making it particularly dangerous in multi-tenant environments where credential isolation is critical for security.
Organizations should implement immediate mitigations including upgrading to Credhub release versions that address this vulnerability, typically those released after the patch was made available. The recommended approach involves disabling the interpolate endpoint functionality if it is not essential for operations, or ensuring that proper network segmentation and application-level access controls are implemented to limit exposure. Additionally, administrators should conduct thorough audits of credential access patterns and implement monitoring solutions to detect unauthorized access attempts. This vulnerability aligns with CWE-284 Access Control Issues and maps to ATT&CK technique T1552.001 for Unsecured Credentials, emphasizing the importance of proper authorization controls in credential management systems. The incident underscores the critical need for comprehensive security testing of access control mechanisms and proper validation of authentication states within all application endpoints.