What is Kubernetes Security? 

Kubernetes – also known as K8s – is an open-source, container-orchestration platform for managing containerized workloads and services. Kubernetes is in charge of container deployment and also manages the software-defined networking layer that allows containers to talk to one another. The platform is portable and facilitates declarative configuration and automation.

The official Kubernetes website states, “The name Kubernetes originates from Greek, meaning helmsman or pilot. Google open-sourced the Kubernetes project in 2014. Kubernetes combines over 15 years of Google's experience running production workloads at scale with best-of-breed ideas and practices from the community.”

Kubernetes plays a critical role in managing the scale and complexity of containerized applications by grouping and managing the various containers that run your applications. Containers are constantly being spun up and replaced, so Kubernetes will immediately swap a container to ensure there is no down time.

But, what exactly is a container? According to Gartner, containers simplify application packaging and enable rapid application deployment. This enables platform consistency across development, testing, and staging. It also helps to accelerate builds and software releases, leading to more repeatable processes.

Why is Kubernetes Security Important? 

Kubernetes is important because it abstracts container management and orchestration and automates a task that would otherwise be impossible for humans to manage at scale. In a lot of ways, it's a foundational component of achieving what DevOps teams are trying to accomplish when setting up a continuous integration/continuous deployment (CI/CD) pipeline.

Security risks come into play when that human element is taken away – analysts are now trusting a system to manage the environment, based on a set of declarative policies and commands. To ensure this is done securely, guardrails should be implemented and operations continuously monitored within Kubernetes-based applications. This ensures any compliance drift or anomalous/suspicious behavior is caught and attended to.

Because of its benefits, Kubernetes has quickly become a de facto orchestration tool for many enterprise DevOps teams. As a result, cloud service providers like AWS, Azure and GCP have released managed versions of Kubernetes (EKS, AKS, and GKE, respectively) which almost entirely remove the need to manage and monitor the kubernetes nodes and clusters

The practice of integrating security into your DevOps process is known as DevSecOps. Building security checks and guardrails into the development process can be extremely beneficial, both with respect to enabling development teams to iterate quickly without sacrificing security and compliance as well as by allowing teams to catch issues before they ever reach production environments.

Kubernetes Security Challenges

Kubernetes operations can be complicated processes to secure. Done successfully, it can securely accelerate your development process in a manner that doesn’t increase your risk posture. Let’s take a look at some more prominent issues that can surface when shifting security left into Kubernetes operations.

Runtime monitoring 

This process watches an application at runtime (when it is in production) to block potentially malicious activity. The challenge comes in surfacing relevant insights like alerts, and threat findings. These findings are often missing much of the context needed to perform quickly and conduct proper investigations with confidence. Automating the process for continuous monitoring can increase a DevSecOps team’s efficiency, but it also forces the relinquishment of some control, which can lead to security concerns.

Security control configuration

Small misconfigurations can lead to big vulnerabilities. Making changes to Kubernetes resources in one instance can lead to those changes being overwritten later if they are not tracked. That can lead to unforeseen vulnerabilities even if security checks are working as they should. Version controlling enables a quick restoration to a prior configuration state if a vulnerability or security issue is detected.

Secure workload deployment

Securing Kubernetes containers is the biggest challenge of all. Of course, there are many solutions on the market to mitigate any vulnerabilities or attacks that may show up in this process. Deploying multiple containers at once can be especially difficult to secure. This would be a case for scaling up the deployment, which can also add complexity. Leveraging a single-policy framework to enforce across all Kubernetes workloads can ensure risks are flagged and cloud deployment is protected from malicious attacks.

Image and registry misuse 

Leveraging a container image from a registry can speed along the process, but those images might contain malicious code. Indeed, building tools like vulnerability scanning into the process is a must when working with Kubernetes containers that exist on publicly available registries.

Privately storing container images and leveraging vulnerability scanning can ensure that a development pipeline is seeing as little exposure as possible to publicly available resources and container images. Speed can also be a liability, especially if a team skips the step of correlating image vulnerability with already-deployed container images. This comparison is critical in understanding the risk posed to your network.

So, what are the most critical parts of securing Kubernetes operations?

  • Configuration: Implement a security solution that can continuously scan and enforce proper configuration of your nodes, clusters and pods. 
  • Operation: Audit logs help ensure that any traffic during operation is non-malicious. Real-time forensics and analysis automation enable early detection and can significantly reduce noise. 
  • Runtime: Monitoring during runtime is as critical as any security check that comes prior to deployment. This helps to keep the process secure, from start to finish. 

Kubernetes Security Best Practices 

What we’ve covered so far should communicate one very important piece of information: Kubernetes is very beneficial, but should be leveraged carefully and methodically. To that point, integrating best practices into a Kubernetes workstream is critical when learning the process and ramping up.

Use role-based access controls (RBACs) 

RBACs allows you to configure user access and effectively manage data and user bases as they grow in size and complexity. Assign products, roles, and resources so that users only have access to the information necessary for their roles. This encourages the principle of least privilege, which helps prevent users from accessing sensitive data or information irrelevant to their roles.

Limit API access

APIs control the types of requests applications make between each other, how those requests are made, and what format those requests will take. Because a single application can often incorporate the use of many APIs, they add vulnerabilities to the development and deployment process. Therefore, it’s a good idea to limit access to APIs only to personnel that absolutely need it.

Restrict SSH access

Secure Shell (SSH) helps to secure a development protocol with cryptographic security. It is essentially a shell that blankets information systems with hardened security checks. If the SSH is not secure and defended properly, it can leave cloud applications and Kubernetes workloads open to vulnerability and attack, especially for public companies and systems open to the internet.

Ensure Kubernetes is up-to-date

This probably goes without saying, but the best way to ensure workloads and deployments are protected and properly containerized is to keep Kubernetes up to date. In fact, Kubernetes features rolling updates processes so users can update deployments with zero downtime by incrementally updating instances with new versions.

Perform proactive scanning and monitoring

Continuous and proactive scanning and monitoring can protect against unexpected vulnerabilities and malicious threats. In a recent Market Guide for Cloud Workload Protection Platforms, Gartner stated that workloads are becoming more granular, with shorter life spans. Sometimes multiple iterations are deployed per week or even per day.

A proactive approach is the best way to secure these rapidly changing and short-lived workloads. Pre-deployment vulnerability management and continuous code scanning helps to protect cloud-based workloads from the very beginning through to deployment and runtime.

Maintain Proper Configuration and Security Posture

It's imperative to maintain proper configuration of Kubernetes clusters. As with any other runtime workload, improper configuration could leave a K8s environment vulnerable to breaches. The practice of ensuring correct configuration and security is known as Kubernetes Security Posture Management (KSPM).

KSPM puts into place a system for establishing and maintaining the strength of Kubernetes cluster defenses and ensuring they comply with internal and external security standards. 

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