Understanding Kubernetes Security Posture Management (KSPM)
By now, you’ve likely heard of cloud security posture management, or CSPM, which uses automation to detect and remediate security and compliance issues in the cloud.
But what about Kubernetes security posture management, or KSPM? In a world where more and more workloads are being deployed on Kubernetes, KSPM has become an important complement to CSPM.
Here’s everything you need to know about Kubernetes security posture management and best practices for automating Kubernetes security and compliance.
What Is Kubernetes Security Posture Management?
Kubernetes security posture management, or KSPM, is the use of security automation tools to discover and fix security and compliance issues within any component of Kubernetes.
For example, KSPM could detect misconfigurations in a Kubernetes RBAC Role definition that grants a non-admin user permissions that he or she should not have, like the ability to create new pods. Or, a KSPM tool could alert you to an insecure Kubernetes network configuration that allows communication between pods in different namespaces, which would typically not be a setting you would want to enable.
Why Is Kubernetes Security Posture Management Important?
As part of a broader Kubernetes security strategy, KSPM addresses several important security considerations.
Catching Human Errors and Oversights
KSPM is a solution for double-checking the security of the configurations that you use to govern Kubernetes resources. No matter how hard engineers work to ensure that the configurations they create are secure by default, there is always a risk that human error or oversight will lead to configurations that are not as secure as they ideally would be.
KSPM helps teams find and fix these mistakes before they lead to breaches.
Managing Security as Clusters Evolve
Kubernetes is still a rapidly evolving technology, and configurations that are secure for one version of Kubernetes may cease to be secure if you upgrade to a new version.
For instance, Kubernetes announced in 2021 that pod security policies, which were once a critical resource for enforcing certain types of access control over pods, are being deprecated. Current versions of Kubernetes still enforce pod security policies, but support will end with version 1.25. If you are still using pod security policies when you upgrade to version 1.25, a KSPM tool could alert you to the fact that Kubernetes is ignoring your policies, and that you should replace them with tools like Kubernetes security contexts or custom admissions controllers.
Validating Third-Party Configurations
Kubernetes is an ecosystem where teams routinely borrow or import resources from upstream. You may pull container images from a public Docker Hub registry, for instance, or apply a deployment file that you found on GitHub. The third-party developers who create those resources may or may not follow the same security conventions as your own team.
KSPM offers a means of scanning third-party resources for possible security issues. In turn, it allows you to take advantage of the rich resources that the Kubernetes community offers while managing the associated security risks.
Enforcing Kubernetes Compliance
Because KSPM uses policy engines to evaluate configurations and identify risks, it lends itself well to scenarios where businesses need to meet specific compliance requirements.
For example, by writing policies that ensure that any data managed or accessed by Kubernetes is stored in ways that are compliant with frameworks like HIPAA or the GDPR, businesses can automate compliance management within their Kubernetes clusters.
How Does Kubernetes Security Posture Management Work?
Although different tools may take a somewhat different approach to KSPM, KSPM workflows boil down to several key steps.
Define Security Rules
Typically, KSPM tools are powered by policies that define security and compliance risks. Most KSPM tools come with a built-in set of policies, and admins can define their own.
Using security and compliance rules, KSPM tools automatically scan a Kubernetes environment. For each resource that they assess, they look for configurations that violate the predefined rules.
Ideally, configuration scanning will take place continuously so that risks can be identified in real time whenever a new configuration is introduced or an existing one is updated.
Detect, Assess, and Alert
When a policy violation is detected, KSPM tools can typically assess its severity level, then generate an alert or notification if the severity level merits immediate, real-time notification. Minor issues may simply be recorded in a log that the team can address later.
After receiving notice of a security or compliance policy violation, engineers investigate and remediate the problem. In certain cases, it may be possible with advanced KSPM tooling to remediate issues automatically by, for example, modifying a problematic RBAC file to enhance security.
KSPM vs. CSPM
The relationship between Kubernetes security posture management and cloud security posture management is subjective. You could argue that KSPM is one component of CSPM, given that Kubernetes environments often run in the cloud.
Or, you could view KSPM as a distinct domain because Kubernetes doesn’t have to run in the cloud (it could be deployed on-premises), and the types of resources and configurations that KSPM validates (like Kubernetes RBAC policies) are different from the resources that CSPM can protect (such as cloud IAM policies and cloud networking configurations).
Regardless of how you choose to think about the relationship between KSPM and CSPM, however, what’s important is understanding that KSPM addresses the unique security and compliance risks of Kubernetes, whereas CSPM helps manage risks in other types of cloud-native environments. If you use Kubernetes, then, you need a security tool that offers specific KSPM functionality.
Getting the Most Out of KSPM
While deploying a KSPM tool to help monitor your Kubenetes environment is the first step in mitigating security and compliance risks, teams should follow some key best practices to get the most value out of KSPM.
As noted above, scanning of configurations should happen continuously. Kubernetes environments tend to change constantly as containers are redeployed, namespaces are added or modified, users and service accounts are created or removed, and so on.
Performing continuous scans ensures that you catch security issues soon after they appear. That’s much better than only scanning periodically.
Keep Your Rules Up-To-Date
Kubernetes security and compliance risks are always evolving. So are Kubernetes configurations themselves. If your KSPM tools rely on rules that were designed for an earlier version of Kubernetes, or that are simply outdated, they may not be able to detect the newest types of risks.
Avoid this problem by using policy rules that are continuously updated as the Kubernetes threatscape changes.
Not all security and compliance risks in Kubernetes are equally serious. A container that is allowed to run in privileged mode is likely to be a more serious risk than a user who was mistakenly given list permissions for pods, for example.
To help your team identify and respond to the most serious risks first, use KSPM tools and policies that can not just detect risks, but also categorize them by severity level.
Don’t Rely on KSPM Alone
KSPM is one ingredient in a Kubernetes security strategy, but it’s hardly the only one. It’s not a substitute for runtime security, which helps detect active threats within your environment. Nor does KSPM address risks like malware inside containers, which is a threat that container image scanning can handle.
The point here is that you must deploy a broad set of security tools for Kubernetes. As part of a broader Kubernetes security strategy, KSPM allows teams to validate the security of Kubernetes configurations in order to find and remediate mistakes that could trigger a breach. By performing continuous, automatic scans of Kubernetes configurations, admins can mitigate one of the most common vectors of attack – human error – while at the same time automating compliance in even the most complex of Kubernetes clusters.