Boost Your Kubernetes Security: 6 Essential Strategies Every IT Pro Should Know

Securing a Kubernetes cluster is key to keeping our applications running smoothly and safely. Let’s dive into six essential strategies you should be implementing:

1 — Authentication & Authorization

1. Don’t Overuse system:masters Group: After bootstrapping, make sure you’re not using the system:masters group for user or component authentication.
2. Service Account Credentials: Enable — use-service-account-credentials for the kube-controller-manager.
3. Protect Your Root Certificates: Keep your root certificate secure, whether it’s an offline CA or a managed online CA with strong access controls.
4. Set Certificate Expiry Dates: Make sure your intermediate and leaf certificates expire in no more than 3 years.
5. Avoid system:masters for Everything: Don’t run the entire kube-controller-manager as system:masters.

2 — Network Security

1. Apply Network Policies: Set up ingress and egress network policies for all your workloads.
2. Default Deny Policies: Within each namespace, create default network policies that select all pods and deny everything by default.
3. Encrypt Communications: Consider using a service mesh to encrypt communications within the cluster.
4. Secure Your APIs: Keep the Kubernetes API, kubelet API, and etcd off the public Internet.
5. Cloud Metadata API Access: Filter access from workloads to the cloud metadata API.
6. Restrict LoadBalancer and ExternalIPs: Limit the use of LoadBalancer and ExternalIPs to reduce exposure.

3 — Pod Security

1. Limit RBAC Rights: Only grant RBAC rights to create, update, patch, and delete workloads when necessary.
2. Enforce Pod Security Standards: Apply appropriate Pod Security Standards policies for all namespaces.
3. Set Memory Limits: Define memory limits for workloads to be equal to or less than the requests.
4. Consider CPU Limits: Set CPU limits on sensitive workloads as needed.
5. Enable Seccomp: Use Seccomp with appropriate syscall profiles for your programs.
6. AppArmor or SELinux: Enable AppArmor or SELinux with suitable profiles for nodes that support these security mechanisms.

4 — Logs and Auditing

1. Protect Audit Logs: If you have audit logs enabled, make sure they are protected from general access.
2. Disable /logs API: Turn off the /logs API to reduce unnecessary exposure.
3. Limit /var/log Content: Restrict the content of /var/log to Kubernetes API server logs only within the host or container where the API server runs.

5 — Secrets

1. Avoid ConfigMaps for Confidential Data: Don’t use ConfigMaps to store sensitive information.
2. Encrypt Secrets at Rest: Set up encryption at rest for the Secret API.
3. Inject Third-Party Secrets: If appropriate, deploy mechanisms to inject secrets stored in third-party storage.
4. Restrict Service Account Tokens: Don’t mount service account tokens in pods that don’t need them.
5. Use Bound Service Account Tokens: Opt for bound service account token volumes instead of non-expiring tokens.

6 — Images

1. Minimize Container Image Content: Keep unnecessary content out of your container images.
2. Run as Unprivileged Users: Configure container images to run as unprivileged users.
3. Reference by sha256 Digests: Use sha256 digests to reference container images via admission control rather than tags.
4. Regular Image Scanning: Regularly scan container images during creation and deployment, and patch known vulnerabilities.

By implementing these strategies, you’ll boost the security of your Kubernetes clusters and ensure robust protection against potential threats. Stay secure out there!