As Kubernetes solidifies its position as the standard for container orchestration, it’s imperative to examine the associated security challenges. Kubernetes brings powerful capabilities to the enterprise and introduces new attack vectors and potential vulnerabilities. Here at Kublr, we sat down with our best experts to discuss how our team solves security challenges and how Kublr helps clients mitigate them.
Inherent Complexities and Misconfigurations
Kubernetes is inherently complex, with a steep learning curve. This complexity often leads to misconfigurations, which, in turn, can present significant security vulnerabilities.
To mitigate this, businesses must invest in comprehensive training and experienced consulting to ensure their developers and IT staff fully understand Kubernetes and its security implications.
How Kublr can help: We help to reduce complexity in two ways - Kublr platform is designed to make setting up Kubernetes clusters easier, faster, and less complex by providing a unified and transparent setup experience across multiple cloud and premise providers and by offering expert solutions architect and DevOps consulting, bringing the risks of the misconfiguration down.
Insufficient Segmentation
Within a Kubernetes cluster, various applications may run concurrently, each within their pods. A compromised pod can potentially allow attackers to access other pods within the cluster without proper segmentation.
One way to address this is by implementing network policies that provide granular control over communication between pods. Using a CNI (Container Network Interface) that supports network policies, such as Calico or Cilium, is a step in the right direction. Further isolation can be achieved by segregating sensitive workloads into separate namespaces.
How Kublr can help: We plan to release network policy support for Cilium in December 2023, in the upcoming 1.28 Kublr release. Although it’s already supported by customized Cluster Specification, in the next release, we plan to fully support Cilium Network policies in our UI, making its usage even more accessible and more transparent by a simple selection in our setup flow.
API Server Exposure
The Kubernetes API server is a crucial component, as it interprets and executes the commands from Kubectl, the Kubernetes dashboard, and other clients. If exposed, it can be a potential attack surface.
API server exposure can be mitigated by ensuring it is not publicly accessible online. Use a combination of authentication, authorization, and admission control mechanisms to secure API server access. For instance, RBAC (Role-Based Access Control) can limit users' permissions to interact with the API server. Admission controllers like OPA/Gatekeeper can enforce policies that dictate what resources can be created or modified.
How Kublr can help: You can opt-out from using an external API server and use Kublr API to depersonalize and use it as a proxy. Also, this way, you don’t need to give away access to your cloud setup to different people. Using a proper RBAC configuration will give you the option to set up optimal identity management and keep the number of credentials to access the setup lower. This way, your engineers don’t need all the different cloud credentials; they just need access to Kublr.
Insecure Images and Containers
Containers are as secure as the images they’re built from. If an image is compromised, every container instantiated from it is potentially a threat.
Organizations must implement a secure software supply chain. This includes using only trusted images from reliable registries, scanning for vulnerabilities, and signing images to ensure integrity. Tools like Docker Bench for Security or Clair can be helpful for image scanning.
How Kublr can help: We’re researching the best way to solve this problem. The current solution we’re looking at now includes signing images with Cosign, which will be available in the upcoming release. For now, every solution we deal with is custom, and we provide consultations on the best practices to do it.
Unrestricted Access and Permissions
Unrestricted access to Kubernetes resources can pose significant security risks, as an attacker could take over control if they gain access.
To handle this, implement the principle of least privilege (PoLP), ensuring that users and service accounts only have the minimum permissions necessary to perform their tasks. Kubernetes supports RBAC, which can be used to define roles and permissions at a granular level.
How Kublr can help: Kublr makes configuring RBAC a much easier job by doing it within our UI. This helps set up permissions faster and makes it less confusing. We also have an internal audit service, we audit requests to our API, and we do an audit of the pre-set Kubernetes Cluster’s API.
Logging and Monitoring Gaps
Detecting a security breach can be like finding a needle in a haystack without proper logging and monitoring.
Use logging and monitoring tools that support Kubernetes, like Prometheus for monitoring and Fluentd or Loki for logging. These tools can help identify abnormal behavior, enabling quick response to potential security incidents.
How Kublr can help: We’re using Elastic or/and Open Search for logging all the info on the clusters right out of the box, and we use different solutions like Prometheus, Grafana, VictoriaMetrics, or Alertmanager for the monitoring of Kubernetes, business application and the state of the logging system.
Inadequate Encryption
Data transmitted within a Kubernetes cluster or stored at rest in etcd, the Kubernetes backing store, may be vulnerable if not properly encrypted.
To overcome this, ensure all data in transit is encrypted using TLS. For data at rest in etcd, Kubernetes supports encryption at the application layer, which can be used to safeguard sensitive information.
How Kublr can help: We can help encrypt the disks to protect the data from the disks being leaked into the cloud. All the other options are, from our experience, mostly custom, which can be done using Kublr custom cluster specifications, like service mesh. In the next release, Kublr Users can configure Cilium when creating a cluster, allowing for more straightforward network policy setup and traffic encryption.
In conclusion, while Kubernetes orchestration platforms bring numerous benefits, they also present distinct security challenges. The complex nature of Kubernetes and its widespread adoption make it a tempting target for attackers. However, with the proper safeguards, these risks can be significantly mitigated. Using Kublr’s out-of-the-box solution functionality can help protect your Kubernetes deployments, keeping your applications secure and your business thriving. And if you have a complex case - the best way to keep it secure is to get experienced solution architects on board to train your team and plan your setup, to minimize the security risks.