What are the best practices for managing Kubernetes secrets?

Managing Kubernetes secrets effectively is crucial to maintaining the security and integrity of your applications and infrastructure. Here are the best practices for handling Kubernetes secrets:

1. Use Kubernetes Secrets Object

Store sensitive information like passwords, API keys, and certificates in Kubernetes Secret objects rather than embedding them directly in configurations or environment variables.
Secrets are base64 encoded, not encrypted by default, so additional measures are required for securing them.

2. Enable Encryption at Rest

Configure Kubernetes to encrypt secrets at rest using an encryption provider (e.g., AES-256). This ensures that even if the etcd database is compromised, secrets remain secure.
Update the EncryptionConfiguration file in the Kubernetes API server configuration.

yaml kind: EncryptionConfiguration apiVersion: apiserver.config.k8s.io/v1 resources: - resources: - secrets providers: - aescbc: keys: - name: key1 secret: <base64-encoded-key> - identity: {}

3. Restrict Access Using RBAC

Use Role-Based Access Control (RBAC) to limit who can view, create, or modify secrets. Define roles and role bindings carefully to ensure secrets are only accessible to authorized personnel and services.
For example, create a role that grants access only to specific secrets:

yaml kind: Role apiVersion: rbac.authorization.k8s.io/v1 metadata: namespace: default name: secret-reader rules: - apiGroups: [""] resources: ["secrets"] verbs: ["get"]

4. Avoid Hardcoding Secrets

Do not hardcode secrets in application code, deployment manifests, or container images. Instead, reference secrets through environment variables or volume mounts.

Example: Mounting a secret as an environment variable in a pod:
yaml env: - name: DB_PASSWORD valueFrom: secretKeyRef: name: db-secret key: password

5. Use External Secret Management Tools

Integrate Kubernetes with external secret management tools like HashiCorp Vault, AWS Secrets Manager, Azure Key Vault, or Google Secret Manager. These tools provide better security, auditing, and lifecycle management.
Use solutions like External Secrets Operator to sync secrets from external systems to Kubernetes.

6. Implement Secret Rotation

Regularly rotate secrets to minimize the impact of accidental exposure or compromise. Automate secret rotation using external secret managers or custom scripts.
Ensure that applications can dynamically reload updated secrets without requiring downtime.

7. Audit and Monitor Secrets Usage

Continuously audit access to secrets using Kubernetes audit logs or external logging solutions.
Monitor for unauthorized access or suspicious activity using tools like Prometheus, Grafana, or third-party security monitoring solutions.

8. Avoid Plaintext Secrets in CI/CD Pipelines

Do not expose secrets as plaintext in CI/CD pipelines. Use secret management tools or Kubernetes secrets injection mechanisms to securely pass sensitive data to build and deployment processes.

9. Limit Secret Exposure in Logs

Ensure applications and Kubernetes components do not log sensitive information inadvertently. Configure logging systems to scrub secrets from logs.

10. Secure Secrets in Transit

Use TLS/SSL to encrypt communication between Kubernetes components and applications to prevent interception of secrets during transit.

11. Namespace Isolation for Secrets

Organize secrets by namespace and ensure they are isolated between applications or teams to reduce the blast radius in case of a compromise.

12. Use Immutable Secrets

When possible, mark secrets as immutable. This prevents accidental or malicious modification of the secret once it’s created.

yaml kubectl create secret generic my-secret --from-literal=username=admin --from-literal=password=secret --immutable=true

13. Backup Secrets Securely

Back up secrets as part of your etcd backup process. Ensure the backups are encrypted and stored in a secure location.

14. Delete Unused Secrets

Regularly audit and clean up unused secrets to reduce clutter and minimize potential attack surfaces.

15. Leverage Tools for Secret Management

Use tools like kubectl, kustomize, or Helm charts to manage secrets securely and consistently across environments.

By following these best practices, you can ensure the security and proper management of Kubernetes secrets, reducing the risk of exposure and maintaining the integrity of your infrastructure.