CVE-2018-18264 in Kubernetes Dashboard
Summary
by MITRE
Kubernetes Dashboard before 1.10.1 allows attackers to bypass authentication and use Dashboard's Service Account for reading secrets within the cluster.
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Analysis
by VulDB Data Team • 06/22/2023
The vulnerability identified as CVE-2018-18264 affects Kubernetes Dashboard versions prior to 1.10.1, representing a critical authentication bypass flaw that enables unauthorized access to cluster resources. This vulnerability specifically targets the Kubernetes Dashboard component which serves as a web-based user interface for managing Kubernetes clusters. The flaw arises from improper authentication handling within the dashboard's service account mechanism, allowing attackers to exploit a weakness in the access control system. The vulnerability is particularly dangerous because it enables attackers to leverage the Dashboard's built-in service account privileges to access sensitive cluster information, including secrets stored within the Kubernetes environment. This represents a direct violation of the principle of least privilege and demonstrates a fundamental flaw in how the dashboard handles authentication contexts.
The technical implementation of this vulnerability stems from how the Kubernetes Dashboard processes authentication requests and service account tokens. Attackers can bypass the standard authentication flow by manipulating the dashboard's API endpoints to utilize the Dashboard's own service account credentials instead of requiring proper user authentication. This allows the attacker to perform actions that should be restricted to authenticated users with appropriate permissions. The flaw specifically affects the dashboard's ability to properly validate and enforce authentication boundaries, creating a path for privilege escalation and unauthorized access to cluster resources. The vulnerability is classified under CWE-287 which deals with improper authentication mechanisms, and aligns with ATT&CK technique T1078 for valid accounts and T1566 for social engineering through credential access. The dashboard's service account typically possesses elevated privileges within the cluster, making this vulnerability particularly impactful for attackers seeking to gain deeper access to cluster resources.
The operational impact of CVE-2018-18264 extends beyond simple unauthorized access, as it enables attackers to extract sensitive information from the cluster including API keys, passwords, certificates, and other confidential data stored in Kubernetes secrets. This can lead to complete cluster compromise and lateral movement within the infrastructure. The vulnerability affects organizations using older versions of Kubernetes Dashboard, particularly those running versions before 1.10.1, where the authentication bypass was not properly addressed. Attackers can exploit this vulnerability to gain access to the entire cluster's secrets management system, potentially leading to data breaches, service disruption, and further compromise of the underlying infrastructure. The impact is amplified because the dashboard is often exposed to external networks without proper security controls, making it an attractive target for attackers seeking to exploit authentication weaknesses. Organizations may experience significant operational disruption and security incidents when this vulnerability is exploited, as it provides a direct path to sensitive cluster information without requiring complex attack vectors.
Mitigation strategies for CVE-2018-18264 primarily focus on updating the Kubernetes Dashboard to version 1.10.1 or later, which includes proper authentication enforcement and fixes the service account token handling mechanism. Organizations should also implement network segmentation to restrict access to the dashboard endpoint, ensuring that it is not exposed to untrusted networks. Additional security measures include enabling proper authentication mechanisms such as OAuth2 or LDAP integration, implementing strict network policies to limit access to the dashboard service, and regularly auditing dashboard access logs for suspicious activity. Security teams should also consider implementing role-based access controls that limit the privileges of the dashboard's service account to only necessary cluster operations. The vulnerability highlights the importance of keeping Kubernetes components updated and maintaining proper security configurations. Organizations should conduct regular vulnerability assessments and penetration testing to identify similar authentication bypass vulnerabilities within their Kubernetes environments. Furthermore, implementing monitoring and alerting for unauthorized access attempts to cluster secrets and service accounts provides additional defense-in-depth measures. The fix for this vulnerability aligns with security best practices recommended by the Kubernetes security team and addresses the specific weakness in the dashboard's authentication handling that allowed attackers to exploit service account privileges without proper authentication.