CVE-2024-42480 in kamaji
Summary
by MITRE • 08/12/2024
Kamaji is the Hosted Control Plane Manager for Kubernetes. In versions 1.0.0 and earlier, Kamaji uses an "open at the top" range definition in RBAC for etcd roles leading to some TCPs API servers being able to read, write, and delete the data of other control planes. This vulnerability is fixed in edge-24.8.2.
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Analysis
by VulDB Data Team • 08/17/2024
Kamaji serves as a Hosted Control Plane Manager for Kubernetes environments, enabling the creation and management of multiple isolated control planes within a single Kubernetes cluster. This architecture allows organizations to provide multi-tenant control plane services while maintaining operational efficiency and resource isolation. The vulnerability exists in versions 1.0.0 and earlier where the Role-Based Access Control implementation for etcd roles contains a critical flaw in the access control model. The specific issue manifests as an "open at the top" range definition that creates an overly permissive access pattern within the RBAC system. This flaw allows certain Tenant Control Plane (TCP) API servers to access the etcd data stores of other control planes, effectively breaking the isolation boundaries that should exist between different tenant control planes.
The technical flaw stems from improper RBAC configuration where the range definition for etcd roles does not adequately restrict access to control plane data. This creates a privilege escalation scenario where one TCP API server can perform read, write, and delete operations on the etcd data of other control planes. The vulnerability represents a direct violation of the principle of least privilege and demonstrates a critical breakdown in the multi-tenancy model that Kamaji is designed to support. The "open at the top" range definition suggests that access controls are configured with overly broad permissions that extend beyond the intended scope of each control plane's administrative boundaries. This flaw essentially allows an attacker with access to one TCP API server to potentially compromise the data integrity, confidentiality, and availability of other tenant control planes within the same Kamaji deployment.
The operational impact of this vulnerability is severe and far-reaching across multiple dimensions of Kubernetes security and multi-tenancy. An attacker exploiting this vulnerability could gain unauthorized access to sensitive control plane data including cluster configurations, authentication tokens, certificate information, and other critical operational data belonging to other tenants. This compromise undermines the fundamental security assumptions of the multi-tenant architecture and could lead to complete control plane takeover scenarios. The vulnerability affects the integrity and confidentiality of the entire Kamaji deployment, potentially enabling attackers to manipulate cluster configurations, escalate privileges, or exfiltrate sensitive data from other control planes. Organizations relying on Kamaji for multi-tenant Kubernetes hosting would face significant risk of cross-tenant data leakage and potential service disruption.
The vulnerability aligns with CWE-284 (Improper Access Control) and represents a specific implementation weakness in the RBAC subsystem that should have enforced strict isolation between control planes. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and credential access, specifically targeting the Kubernetes control plane components. The fix implemented in edge-24.8.2 addresses the root cause by properly configuring the RBAC range definitions for etcd roles, ensuring that each TCP API server can only access its own control plane data. Organizations should immediately upgrade to the patched version to remediate this vulnerability and implement additional monitoring to detect any potential exploitation attempts. Security teams should also review their existing RBAC configurations to ensure that similar "open at the top" patterns are not present in other components of their Kubernetes infrastructure. The vulnerability highlights the critical importance of proper access control implementation in multi-tenant systems and demonstrates the potential for seemingly minor configuration flaws to create significant security risks in complex distributed systems.