Kubernetes comes with a complete set of core software security principles built to make your clusters, workloads, and containers safer. However, none of them is active at the time of deployment. You need to understand the self-configuration process for all the security controls and implement them yourself. Also, Kubernetes security controls are there to support the development of a secure cluster. There are various other security issues to tackle such as malicious actors, malware running inside containers, broken container damages, and compromised or rogue users. The default security controls are not enough to deal with such a wide range of threat vectors. Therefore, you need to make extra efforts to ensure overall security for Kubernetes.
of organizations are already using or planning to use containers in production according to Cloud Native Computing Foundation (CNCF) annual survey.
of organizations are having more than 11 Kubernetes production clusters.
of users experienced at least one Kubernetes security incident in the past year.
of organizations using Kubernetes and containers said that security is their biggest concern.
The Kubernetes services are usually managed by the cloud vendor. But it is a shared responsibility between the user and the service provider to secure it. The vendor takes care of the security of the control plane of the Kubernetes cluster which includes the API Server, scheduler, and controllers. Customers are left with the responsibility of securing the data plane which includes node pools, ingress, networking, service mesh, etc. Cloud Pentesting will help to identify the weaknesses in cloud architecture. But for Kubernetes, you must deploy certain specific measures.
The steps you can take to secure Kubernetes are:
RBAC allows you to manage access to the Kubernetes API and the permissions associated with it. On Kubernetes 1.6 and higher, RBAC is enabled by default. Also, some hosted Kubernetes providers have the RBAC engaged right from the deployment. As Kubernetes covers authorization controllers when RBAC is enabled, you should disengage the legacy Attribute Based Access Control (ABAC).
Not having the Kubernetes environments updated is the most common and basic mistake users make. You can count this as primary negligence in terms of security practices. The latest version is always the most stable one to use as updates come with security patches for previous vulnerabilities. Also, make sure you check the latest version in the test environment before deploying it in production.
The Kube-API server is the operating center of the Kubernetes Clusters and serves as the primary point of access for a Kubernetes cluster. Admins and service accounts can access these APIs through the command-line utility kubectl, REST API calls, or other client SDKs. You should always adopt an API authentication method for API servers. Two common authentication methods are simple certificates or bearer tokens. Large-scale entrepreneurship clusters can deploy third-party OpenID Connect providers or Lightweight Directory Access Protocol servers to control group access.
The state of the cluster and all the secret and sensitive resources associated with it are stored in etcd. Therefore, it becomes an attractive target for malicious activities. Unauthorized access to etcd might result in full control of the entire cluster in the wrong hands.
Validating clusters with the help of Center for Internet Security benchmarks associated with specific Kubernetes releases can increase node security. There are node security standards and benchmarks for configuration that you need to follow. Also, you can minimize administrative access to reduce the attack surface area on Kubernetes nodes by limiting administrative access. Furthermore, you need to avoid direct connections to the general corporate network. You can do it by deploying isolation and constraints on nodes.
The key security concerns in Kubernetes are: