CVE-2020-1701 in Kubevirt
Summary
by MITRE • 05/28/2021
A flaw was found in the KubeVirt main virt-handler versions before 0.26.0 regarding the access permissions of virt-handler. An attacker with access to create VMs could attach any secret within their namespace, allowing them to read the contents of that secret.
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Analysis
by VulDB Data Team • 06/03/2021
The vulnerability identified as CVE-2020-1701 represents a critical access control flaw within the KubeVirt virt-handler component that affected versions prior to 0.26.0. This issue resides in the containerized virtualization platform that enables virtual machines to run within Kubernetes clusters, creating a significant security risk for cloud-native environments that rely on KubeVirt for virtualization services. The flaw specifically targets the permission model implemented in the virt-handler daemon responsible for managing virtual machine operations and resource access within Kubernetes namespaces. The vulnerability stems from insufficient validation of secret access permissions during virtual machine creation processes, allowing malicious actors to exploit the system's trust model and escalate their privileges within the namespace boundaries.
The technical implementation of this vulnerability exploits a design weakness in how KubeVirt handles secret references during virtual machine provisioning. When users with appropriate permissions to create virtual machines attempt to attach secrets to their VM configurations, the system fails to properly validate whether the requesting user has legitimate access rights to read the target secret. This oversight occurs in the virt-handler component which processes VM creation requests and manages the attachment of various resources including secrets, configmaps, and other sensitive data. The flaw essentially allows privilege escalation through the secret management system, as the system trusts the user's request without verifying that they possess the necessary authorization to access the referenced secret. This issue falls under the Common Weakness Enumeration category of insufficient authorization checking and can be classified as a privilege escalation vulnerability that violates the principle of least privilege.
The operational impact of CVE-2020-1701 extends beyond simple information disclosure, as it enables attackers to potentially access sensitive credentials, API keys, and other confidential data stored in Kubernetes secrets. An attacker who can create virtual machines within a namespace can leverage this vulnerability to read any secret within that same namespace, potentially gaining access to database credentials, encryption keys, or service account tokens that could be used for further lateral movement within the cluster. This vulnerability particularly affects multi-tenant Kubernetes environments where different teams or applications share the same namespace but should maintain isolation of their sensitive data. The implications are severe as it allows for data exfiltration and can potentially lead to broader compromise of the containerized environment. The attack vector aligns with techniques described in the MITRE ATT&CK framework under the privilege escalation and credential access domains, where attackers exploit misconfigurations to gain unauthorized access to sensitive information.
Mitigation strategies for this vulnerability require immediate implementation of KubeVirt version 0.26.0 or later, which includes the necessary permission validation fixes. Organizations should also implement strict role-based access controls that limit the ability to create virtual machines to only trusted users and service accounts. Additional defensive measures include enabling Kubernetes pod security policies that restrict secret access and implementing network segmentation to limit lateral movement. Security teams should conduct comprehensive audits of their KubeVirt deployments to ensure that no unauthorized users have the ability to create virtual machines within sensitive namespaces. Regular monitoring of VM creation activities and secret access patterns can help detect potential exploitation attempts. The vulnerability highlights the importance of implementing proper access control mechanisms in cloud-native environments and demonstrates the critical need for thorough security testing of containerized virtualization platforms. Organizations should also consider implementing secrets management solutions that provide additional layers of protection beyond the basic Kubernetes secret system.