CVE-2017-15138 in OpenShift Enterprise
Summary
by MITRE
The OpenShift Enterprise cluster-read can access webhook tokens which would allow an attacker with sufficient privileges to view confidential webhook tokens.
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Analysis
by VulDB Data Team • 05/01/2023
The vulnerability identified as CVE-2017-15138 resides within the OpenShift Enterprise platform, specifically concerning access controls for webhook tokens within cluster environments. This issue affects the authorization mechanisms that govern how different user roles interact with sensitive cluster resources. The problem manifests when cluster-read users, who typically possess limited access privileges, can potentially obtain webhook tokens that should be restricted to higher-privilege users. This represents a significant authorization flaw that undermines the principle of least privilege enforcement within the platform's security architecture.
The technical flaw stems from improper access control implementation within OpenShift's webhook token management system. Webhook tokens serve as critical authentication mechanisms for external services to communicate securely with the OpenShift cluster. When cluster-read users can access these tokens, it indicates a failure in the platform's role-based access control (RBAC) implementation. The vulnerability allows unauthorized access to tokens that should remain protected, creating potential attack vectors for privilege escalation. This issue aligns with CWE-284, which addresses improper access control in software systems, and represents a direct violation of the security principle that access to sensitive resources should be strictly controlled based on user roles and permissions.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates opportunities for attackers to escalate privileges and gain unauthorized access to cluster resources. When webhook tokens are exposed to cluster-read users, attackers can potentially impersonate legitimate services or gain access to other cluster components that rely on these tokens for authentication. This vulnerability particularly affects environments where OpenShift clusters interact with external systems through webhooks, as the exposed tokens could enable attackers to manipulate cluster behavior, access sensitive data, or perform unauthorized operations. The impact is compounded by the fact that cluster-read users typically have access to various cluster monitoring and reporting functionalities, providing additional attack surface for exploitation.
Mitigation strategies for CVE-2017-15138 require immediate implementation of enhanced access control measures within OpenShift clusters. Organizations should review and tighten RBAC policies to ensure that webhook token access is restricted to users with legitimate administrative needs. The platform should enforce stricter authorization checks for token retrieval operations, implementing additional validation layers that verify user roles before granting access to sensitive tokens. Security administrators should also implement monitoring solutions that detect unauthorized access attempts to webhook tokens and establish automated alerting mechanisms. This vulnerability demonstrates the importance of regular security assessments and proper privilege management, aligning with ATT&CK technique T1078 which covers valid accounts and privilege escalation through access control bypasses. Organizations should also consider implementing token rotation policies and ensuring that webhook tokens are properly scoped to minimize potential damage from exposure.