You’ve set up Kubernetes for your company, deployed your applications, and everything seems to be running along nice and smoothly. But have you stopped to think about how secure your secrets really are? All of those credentials, API keys, and certificates that you have carefully stored in Kubernetes Secrets—are they truly protected?
The unfortunate truth is that reality may surprise you. Many teams think their sensitive data is locked away securely once it’s tucked away in a Kubernetes Secret, but this confidence often comes from a fundamental misunderstanding of how these secrets really work under the hood. So, let’s take a closer look at what’s actually going on with your sensitive information, and whether or not there is cause for concern.
The False Sense of Security
Let’s jump straight into the main point: Kubernetes Secrets are not encrypted by default. This is a common misconception that many people hold. Instead, the Secrets are simply base64 encoded, which does not provide a great deal of inherent security. In fact, anyone who has access to your cluster would be able to read and decode them.
What happens when you create a Secret? Here is a quick breakdown:
- You provide your sensitive data
- Kubernetes encodes it with base64 (not encryption!)
- It stores this encoded data in etcd (the Kubernetes database)
- Your pods can mount these secrets as files or environment variables
This means that anyone that has access to your etcd will be able to view your Secrets. Anyone with permission to view secrets in the namespace can see them. And if you’re using environment variables, anyone who can exec into your pod can see them too – not exactly the most secure systems in the world.
Real-World Risks You’re Facing
Think about these scenarios:
- A developer with cluster access accidentally commits a script showing secret values to GitHub
- An admin runs kubectl get secrets -o yaml during troubleshooting and leaves the output in logs
- A malicious insider with read access to your cluster exfiltrates all your credentials
- Your etcd backup isn’t properly secured, exposing all historical secrets
These aren’t just theoretical problems and risks—they happen regularly in organizations of all sizes.
To make matters worse, these risks are compounded in typical developer environments. Consider the CI/CD pipeline, which has access to production Secrets for deployment purposes. A compromise there could expose all of your Secrets. From a hardware standpoint, a developer laptop with a Kubectl config that can access multiple clusters means that this device could compromise all Secrets across your environments.
Another danger to consider is the Secret sprawl. As your Kubernetes environment expands, secrets multiply across namespaces, and they can easily (and often are) created with inconsistent management practices. Teams create duplicate secrets with slight variations, and soon, nobody knows which ones are actually in use. This makes rotation nearly impossible and increases your attack surface.
And to put the cherry on top, there’s usually a big issue when monitoring blind spots. Most businesses have no real idea who is using and accessing secrets – or when. Without proper audit trails in place, you won’t be able to tell if someone exported all of your production database credentials, that is, until you see the consequences. At that point, the damage is already done.
Cloud Security Done Right: Better Ways to Handle Your Secrets
So what can you do? Here are some practical approaches to truly protect your secrets:
1. Implement Strict RBAC Policies
The first step is to limit who has access to the ability to read secrets in your cluster:
- Create specific roles that don’t include secret read permissions
- Implement namespace isolation
- Use service accounts with minimal permissions
One of the primary best practice principles of Kubernetes security is the concept of least privilege. This means that your applications and people should only have access to the specific secrets they need – not all of the secrets in the namespace.
With this in mind, try creating separate namespaces for different security boundaries, each with its own tightly controlled set of secrets.
2. Encrypt etcd at Rest
Kubernetes supports encrypting the data in etcd. This prevents anyone accessing the etcd database from viewing your secrets in plain text. Setting this up requires:
- Creating an encryption configuration
- Enabling the encryption provider in your API server
- Re-encrypting your existing secrets
However, while this is undoubtedly an important step, it’s important to remember that this means that data is encrypted when it is at rest (when it is stored). Once you begin using these secrets, you’ll need additional safeguards.
3. Use External Secret Management
Instead of storing secrets directly in Kubernetes, you can use an external secret management system specifically designed for handling sensitive information. These custom-made solutions offer benefits like automatic rotation, temporary credential generation, and comprehensive audit logging.
The integration typically happens through custom controllers that fetch secrets when needed and inject them into your pods. What this means is that your sensitive data never needs to be stored within Kubernetes itself, dramatically reducing your attack surface.
4. Use Temporary, Just-in-Time Credentials
Move away from long-lived static credentials whenever possible. Instead, implement systems that provide temporary access credentials that:
- Automatically expire after a short time period
- Are unique to each instance of your application
- Can be instantly revoked if suspicious activity is detected
The main goal of this approach is to limit your exposure window. Even if your credentials leak, they become useless quite quickly, offering you another layer of protection.
5. Consider Secret Zero Problem
Even with better secret management, you still have the “secret zero” problem—how does your application authenticate to the secret manager? Solutions include:
- Pod identity mechanisms tied to cloud provider IAM systems
- Kubernetes service account tokens
- Certificate-based authentication
This is oftentimes one of the more challenging aspects of secret management. Cloud-native applications can leverage the cloud provider’s identity services, while on-premises deployments might benefit from certificate-based authentication schemes.
Final Word
The main takeaway here is that protecting your secrets isn’t just about compliance checkboxes—it’s about sleeping well at night knowing your customer data and infrastructure aren’t one misclick away from exposure.
The default Kubernetes approach to secrets just doesn’t cut it in today’s threat landscape. In light of this, you need to evaluate your current setup and see if there you can begin making small improvements.. Maybe it’s just encrypting etcd, or perhaps it’s time for a more comprehensive overhaul.
Whatever you choose, remember that perfect cloud security doesn’t exist, but ” better than what we have now” is absolutely achievable.
