Taking Control of Kubernetes: Enforcing Least Privilege to Secure Your Kubernetes Environment

Kubernetes has become the de facto standard for managing containerized workloads in private and public clouds. However, security standards have failed to keep pace, leading to increased risk of cyberattacks and data breaches for insecure or misconfigured platforms. Here we examine the challenges involved and explain how to protect your Kubernetes environment by enforcing least privilege across all deployments – whether on-premises or hosted in the public cloud.

Enforcing least privilege access in Kubernetes environments is fundamental to maintaining the security posture of the applications and data running throughout the orchestration platform. Because Kubernetes manages containerized applications across on-premises and cloud environments, the security challenges vary slightly. This is primarily due to the inherent differences in infrastructure management and integration capabilities, and a lack of clarity regarding the shared responsibility model in cloud services.

In this blog, we’ll outline the different challenges of enforcing least-privilege access in on-premises and cloud-based Kubernetes environments, and offer recommendations for overcoming these difficulties.

Least-privilege obstacles in on-prem and cloud-based Kubernetes

These are some difficulties you may encounter when trying to enforce least-privilege access in on on-premises Kubernetes deployments:

1. Complex configuration management: On-premises environments require manual setup and configuration, making it challenging to consistently apply least-privilege principles across all nodes and clusters. Monitoring Kubernetes’ many complex configuration files requires significant resources, meaning misconfigurations regularly go unnoticed, leading to overly permissive roles and service accounts.
2. Lack of integrated identity management: Integrating Kubernetes role-based access control (RBAC) with existing enterprise identity-management systems can be challenging in on-premises deployments due to lack of granularity and cloud native capabilities of traditional identity management tools. This results in insufficient visibility, leaving security teams blind to excessive privilege risks and unable to enforce consistent access policies.
3. Network security: Ensuring that only authorized users can access specific Kubernetes resources requires sophisticated network policies. Out of the box, on-premises deployments lack the advanced network security tools available in cloud environments, making it harder to restrict access effectively.
4. Monitoring and auditing: Implementing comprehensive monitoring and auditing to track access and privileges can be more challenging on-premises due to the need for customized implementation of monitoring and auditing tools, which are essential for detecting and mitigating excessive permissions.

Meanwhile, these are some least-privileged stumbling blocks in cloud-based Kubernetes services, such as Amazon Elastic Kubernetes Service (Amazon EKS), Azure Kubernetes Service (AKS) and Google Kubernetes Engine (GKE).

1. Integration with cloud IAM: While cloud providers offer integration with their identity and access management (IAM) services, aligning cloud IAM roles with Kubernetes RBAC for fine-grained access control requires careful planning and configuration by skilled security teams to avoid privilege-escalation risks.
2. Shared responsibility model: In cloud environments, the provider is responsible for securing the infrastructure, and the user is responsible for securing their applications and configurations. This model creates ambiguity around responsibility boundaries, leading to confusion from end users and gaps in access control policies.
3. Automated scalability and dynamic resources: The dynamic scaling of resources in cloud-based Kubernetes can complicate access control. Automatically applied policies rarely adhere to least privilege principles, especially when new instances or services are spun up rapidly.
4. Multi-tenancy and isolation: Ensuring strict isolation between different applications in a shared Kubernetes environment is crucial. Cloud providers offer tools to assist with namespace isolation, but ensuring that secure configuration and controls are enforced requires complex and continuous scrutiny.

How to tackle these obstacles

Here are some common strategies for addressing these challenges:

• Embrace Kubernetes RBAC: Both on-premises and cloud deployments should use Kubernetes RBAC to define and apply roles and permissions granularly. Most importantly, understanding the requirements of cluster-wide and namespace-specific roles is crucial to the successful enforcement of least privilege.
• Use namespace strategies for isolation: Namespaces can be used effectively to segregate resources and control access at a more granular level, suitable for both on-premises and cloud deployments. Ensure that roles are restricted to specific namespaces to isolate the blast radius of compromises.
• Integrate with existing IAM: For cloud deployments, integrate Kubernetes RBAC with cloud IAM roles. For on-premises deployments, integrate with LDAP or Active Directory by ensuring that you have a clear understanding of each security model and the required privileges.
• Adopt policy-as-code: Utilize tools like Open Policy Agent (OPA) to define and enforce security policies as code, ensuring consistent application across environments. Policy-as-code can be essential to gaining a normalized view of your Kubernetes clusters and enforcing standardized controls across multiple environments.
• Use the correct tools for continuous monitoring and auditing: Implementing third-party continuous monitoring and auditing tooling helps identify and mitigate issues with excessive permissions in real time, minimizing the impact and limiting the blast radius of compromised accounts.

In short, addressing least-privilege access challenges in Kubernetes requires a combination of strategic planning, leveraging of Kubernetes features like RBAC and namespace isolation, and integrating with existing security tools and practices. The complexity of managing access controls can be mitigated by adopting automation, policy-as-code, and continuous security practices, regardless of whether the deployment is on-premises or in a cloud environment.

To get answers to the most commonly asked questions about Kubernetes security, watch our on-demand webinar “Kubernetes Confessions: Tune In and Get the Help You Need to Finally Put An End to Those Risky K8s Security Sins.”

For more on how Tenable Cloud Security can help you secure your Kubernetes environments, view the solution brief "Automated Security and Compliance for Kubernetes."