Kubernetes (K8s) Security

Containers are the fundamental building block of modern applications. Kubernetes (K8s) is the most popular platform for the orchestration of containers, and as a result, Kubernetes security is one of the most important aspects of container security.

What is Kubernetes Security?

Kubernetes security is a set of strategies, techniques, and technologies designed to secure the Kubernetes platform and containers it orchestrates. In other words, K8s security is all about keeping your container workloads secure.

At a high level, this means:

• Understanding And Securing the 4 Cs Of Cloud Native Security: Cloud, Cluster, Container, And Code. Kubernetes 4 Cs model breaks cloud native security into 4 distinct layers. “K8s security” focuses mostly on the cluster layer, but for true end-to-end security, each of these layers must be adequately protected from threats.
• Following Best Practices for Pod Container Security. Getting pod security policies and security contexts are important aspects of K8s security.
• Securing the K8s API. The K8s application programming interface (API) is a big part of what makes Kubernetes so extensible and scalable. It’s also a large attack surface attackers can exploit if not properly secured.

The Importance of Kubernetes Security

Kubernetes can help reduce issues with container security by reducing room for human error and making it possible to programmatically scale secure configurations. However, Kubernetes is also complex, widely used, and part of critical infrastructure in a wide range of use cases. Additionally, as vulnerabilities like CVE-2020-8554 and CVE-2021-25735 have taught us, Kubernetes native security issues can happen.

As a result, the K8s platform is a high-value attack surface hackers aim to compromise. This means enterprises that use containers and Kubernetes in production must take K8s security seriously.

Kubernetes Security Issues

Beyond specific CVEs, there are a variety of security issues and tradeoffs to consider when it comes to Kubernetes security.

Major K8s security issues to consider include:

• The Human Element of K8s Security. While technical solutions are an important part of Kubernetes security, enterprises must consider the human element. In addition to ensuring only authorized users and workstations perform K8s administrative tasks, training administrators on security best practices and making security a priority goes a long way.
• K8s and Container Configuration Management. Many K8s default settings aren’t the most secure option. Administrators need to ensure that their Kubernetes configurations strike the right balance between security and usability. Additionally, using K8s Secrets — instead of plaintext configuration files — for authentication tokens, SSH keys, and other privileged information is important.
• K8s Network Security. Encrypting data in transit should be table stakes for most production workloads. Additionally, network policies should be fine-tuned to restrict unnecessary east-west traffic and help to enable micro-segmentation across clusters.
• K8s Storage. Just as the encryption of data in transit is a must, the encryption of data at rest is an important aspect of K8s security. Enterprises must consider compliance and data security when making decisions on how — and what type of — storage they mount.
• Patch Management. Invariably, new security issues and vulnerabilities arise. Whether they are related to your underlying infrastructure, the K8s platform directly, container images, or dependencies in your code, you need a patch management plan to mitigate them.
• Compliance. Regulations like PCI-DSS, HIPAA, and SOX all come with specific requirements that could directly impact decisions around K8s security.

Kubernetes Security Best Practices

While there is no one-size-fits-all Kubernetes native security solution, there are several K8s security best practices that can help you enhance your overall security posture.

• Follow The Principle of Least Privilege. In general, only allow users and containers to perform the minimum number of actions required to complete their business function. For K8s security, this means doing things such as setting allowPrivilegeEscalation: false in pod manifests and leveraging features like the AppArmor kernel security module.
• Make Security “Everyone’s Responsibility”. The “security is everyone’s responsibility” mantra is popular for a reason: human error creates major security risks. By ensuring everyone involved in getting your app built, tested, and deployed takes security seriously, you can reduce the risk of a breach.
• Integrate Security into Your Pipeline. Automating the process of securing your K8s infrastructure helps eliminate room for human error or misconfiguration. With K8s and container security, shifting security left can go a long way.
• Limit API Access. In addition to encrypting all API traffic, you should implement access controls that limit who can access the K8s API and what specific users can do once they’re authenticated. As an example, the Kubernetes’ docs provide a good starting point for K8s API hardening.
• Restrict SSH Access to K8s Nodes. By limiting SSH access to K8s nodes, you can greatly reduce overall attack surface. If users need to access containers, consider something like the kubectl exec command instead of direct SSH access to the K8s node.
• Select a Security Context That Matches Your Use Case. Different usage scenarios call for different K8s security contexts. Make sure your configurations use the most secure context possible.
• Segment Your K8s Networks. Network segmentation between applications reduces the likelihood a single compromised app brings down your entire infrastructure. K8s network policies, as well as 3rd party security solutions, can help you implement network segmentation in your clusters.
• Use Resource Quotas. Running containers without resource quotas defined creates a variety of unnecessary risks (e.g. increased exposure to DoS attacks). Implementing resource quotas on pods, CPU, and memory can help limit your risk.
• Perform Proactive Scanning and Monitoring. Detecting attacks, unpatched software, anomalous behavior, and breaches as soon as possible goes a long way in limiting dwell time and improving overall security posture. Tools purpose-built for Kubernetes security can help you improve your overall visibility and response times when a problem arises.

Enhance Your Kubernetes Security with Check Point

These K8s security best practices provide a great starting point for securing your Kubernetes infrastructure. Achieving true end-to-end security in the cloud requires a purpose-built solution that can help you keep all your workloads secure, even in multi-cloud environments. With Check Point, you can do just that. Check Point offers the following, across a variety of platforms including Kubernetes.

• Cloud network security and threat prevention
• Application security (including API protection)
• Protection for containers and serverless platforms
• Cloud security posture management