Kubernetes security is an important aspect that companies shouldn’t ignore. Any mistake in securing the cluster could lead to a data leaks, unauthorized access between microservices, running malware, and much more. The scenarios are numerous, and it’s difficult to mention them all.

Your responsibility depends on your Kubernetes cluster—whether it is self-managed or managed by a cloud provider.

I will list the steps to secure your cluster and highlight those that are specific to a self-managed cluster. For cloud-managed clusters, security will generally be the responsibility of the cloud provider.

Cluster Setup

1- Use network security policies to restrict cluster-level access.

2- Use the CIS benchmark to review the security configuration of Kubernetes components (etcd, kubelet, kubedns, kubeapi). (self-managed cluster)

3- Properly set up Ingress with TLS.

Protect node metadata and endpoints. (self-managed cluster)

4- Verify platform binaries before deploying. (self-managed cluster)

Cluster Hardening

1- Use Role-Based Access Control (RBAC) to minimize exposure.

2- Exercise caution when using service accounts, e.g., disable default accounts and minimize permissions for newly created ones.

3- Restrict access to the Kubernetes API.

4- Upgrade Kubernetes to avoid vulnerabilities.

System Hardening

1- Minimize the host OS footprint (reduce the attack surface). (self-managed cluster)

2- Use least-privilege identity and access management (IAM).

3- Minimize external access to the network.

4- Appropriately use kernel hardening tools, such as AppArmor and seccomp. (self-managed cluster)

Minimize Microservice Vulnerabilities

1- Use appropriate pod security standards.

2- Manage Kubernetes secrets securely.

3- Understand and implement isolation techniques (multi-tenancy, sandboxed containers, etc.).

4- Implement pod-to-pod encryption using Cilium.

Supply Chain Security

1- Minimize base image footprint.

2- Understand your supply chain (e.g., SBOM, CI/CD, artifact repositories).

3- Secure your supply chain (permitted registries, sign and validate artifacts, etc.).

4- Perform static analysis of user workloads and container images (e.g., Kubesec, KubeLinter).

Monitoring, Logging, and Runtime Security

1- Perform behavioral analytics to detect malicious activities.

2- Detect threats within physical infrastructure, apps, networks, data, users, and workloads.

3- Investigate and identify phases of attack and bad actors within the environment.

4- Ensure immutability of containers at runtime.

5- Use Kubernetes audit logs to monitor access.

In upcoming blogs, we will go through each step, explain the necessary actions to follow, and discuss the consequences of skipping each step.