Securing Service Meshes with Authorization Policies and Non-Human Identities

Understanding the Need for Service Mesh Authorization

Service meshes are becoming essential for securing modern microservices. But why is authorization so critical in these environments? Let's delve into the need for robust authorization policies within service meshes.

Traditional security models struggle with the complexities of distributed microservices. Unlike monolithic applications, microservices communicate across numerous network boundaries, which significantly increases the attack surface. Additionally, the transient nature of Kubernetes Pod IPs renders traditional firewall rules largely ineffective. According to Authorization policy overview, globally-distributed microservices apps make calls across network boundaries, which means more points of entry into your applications, and more opportunities for malicious attacks.

Service meshes offer a unified approach to securing microservices by providing a dedicated infrastructure layer. These meshes enable security policies at both the application (L7) and transport (L3/4) layers, offering features like mutual TLS (mTLS), authentication, and authorization. With a service mesh, you can implement consistent security policies across your entire application, regardless of the underlying infrastructure.

In microservices architectures, Non-Human Identities (NHIs) are critical. NHIs, also known as machine identities or workload identities, represent services and applications rather than human users. Authorization policies must consider NHIs to effectively control service-to-service access.

For example, imagine a healthcare application where a "patient-data" service needs to access a "records" service. The authorization policy should ensure that only the "patient-data" service, identified by its NHI, can access specific endpoints on the "records" service, preventing unauthorized data access.

By understanding the need for service mesh authorization, we set the stage for exploring how authorization policies and Non-Human Identities work together to secure service meshes. The next section will dive into the specifics of authorization policies.

Authorization Policies: The Building Blocks of Service Mesh Security

Authorization policies are the gatekeepers of your service mesh, determining who can access what. Think of them as the detailed instructions that tell your security system exactly how to control traffic.

Authorization policies define granular permissions for workloads. They control what a service or Non-Human Identity (NHI) is allowed to do within the mesh. These policies are flexible and can be applied at different scopes, ensuring that the right level of security is enforced where it's needed most.

• Granular Permissions: Authorization policies specify exactly what actions a service can perform. For example, a policy might allow a "payment-service" to only access the "charge" endpoint of a "billing-service."
• NHI Access Control: As discussed earlier, authorization policies consider Non-Human Identities, ensuring that only authorized services or applications can access specific resources, which is crucial for service-to-service communication.
• Flexible Scope: Policies can be applied mesh-wide for general rules, at the namespace level for broader control, or to individual workloads for very specific permissions. According to Authorization policy overview, you can apply a policy to the entire service mesh, to a namespace, or to an individual workload.

Every authorization policy has three main parts that define its behavior. These components work together to ensure that only legitimate requests are allowed, based on the rules you set.

• Policy Scope (Selector): This defines the target of the policy, specifying which workloads the policy applies to. Without a selector, the policy applies to everything within the scope.
• Action: This specifies whether to ALLOW or DENY requests. For clarity, it's recommended to always specify the action explicitly.
• Rules: These define when the action is triggered based on the source of the request, the operation being performed, and any additional conditions that must be met.

Authorization policies can be applied at different levels within your service mesh. Each level provides a different range of control, allowing you to tailor your security to your specific requirements.

• Mesh-wide Policies: These apply to the entire service mesh, setting a baseline for security across all services. Mesh-wide policies are useful for enforcing organizational standards.
• Namespace Policies: These apply to all workloads within a specific namespace. If you have multiple services within the same namespace that require same policies, this is useful.
• Workload-Specific Policies: These policies use selectors to target specific workloads based on labels.

To restrict a policy to a specific workload, include a selector field, as noted in Authorization policy overview.

Understanding these scopes and how to use selectors is key to crafting effective authorization policies. Next, we will dive deeper into how these policies interact with Non-Human Identities to create a robust security posture.

Implementing Authorization Policies for NHIs

Securing service meshes with authorization policies is crucial, but how do you implement these policies effectively for Non-Human Identities (NHIs)? Let's explore methods to control access based on authenticated identities and other matching criteria.

One powerful method is restricting access based on the authenticated identity of the workload or namespace. You can achieve this using the principals and namespaces fields in your authorization policies.

• Using principals and namespaces: These fields allow you to specify which workloads or namespaces are permitted to access a service. For example, you can allow only workloads with a specific service account to access a sensitive API endpoint.
• Requires mutual TLS (mTLS): This method depends on mutual TLS (mTLS) being enabled in STRICT mode. With mTLS, each service presents a certificate to verify its identity, ensuring secure communication.
• Example: To allow only the frontend service to access the currencyservice, you would specify the frontend service's principal in the principals field of the authorization policy.

Authorization policies also support various matching schemas to provide flexibility in defining rules. You can use exact match, prefix match, suffix match, or presence match for different fields in the policy.

• Matching Schemas: Most fields support a range of matching options. For instance, you can use a prefix match to allow access from any service within a specific domain.
• Wildcard Characters: Wildcard characters such as "*" can be used for prefix and suffix matching. For example, "*.example.com" matches "eng.example.com" or "test.eng.example.com".
• Exceptions: Some fields, like the key under the when section, only support exact match. Therefore, you must specify the exact value for these fields.

Exclusion matching allows you to define conditions under which access should be denied. The notValues, notIpBlocks, and notPorts fields provide a way to specify negative conditions.

• Negative Conditions: These fields let you exclude certain values, IP blocks, or ports from the policy. For example, you can exclude requests to the /healthz path from JWT authentication requirements.
• Example: You can combine exclusion matching with JWT validation to ensure that all requests, except those to a specific health check endpoint, require a valid JWT.
• JWT Validation: This ensures that only authenticated requests are processed, while allowing unauthenticated access to necessary endpoints like health checks.

By implementing authorization policies effectively, you can secure your service mesh and protect your microservices from unauthorized access.

Next, we'll explore how to configure advanced features in authorization policies to enhance your service mesh security.

Advanced Authorization Policy Configuration

Is it possible to block all unencrypted traffic within your service mesh? With advanced authorization policy configuration, you can fine-tune your security measures to ensure only authenticated and encrypted traffic is allowed. Let's explore how to enhance your service mesh security with advanced features in authorization policies.

You can use authorization policies to enforce mutual TLS (mTLS) and reject plaintext traffic. This is especially important if you cannot enable STRICT mTLS mode for a workload or namespace.

• Enforce mTLS: Create policies that explicitly allow traffic with non-empty namespaces or principals.
• Deny Plaintext: Reject traffic with empty namespaces or principals, effectively blocking any plaintext traffic, as mentioned in Authorization policy overview.
• Example: The following policy denies requests if the principal is empty, which is typical for plaintext requests.

apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
  name: require-mtls
  namespace: NAMESPACE
spec:
  action: DENY
  rules:
  - from:
    - source:
        notPrincipals: ["*"]

When configuring ALLOW and DENY policies, understanding policy precedence is crucial. DENY policies are evaluated before ALLOW policies, ensuring that critical restrictions are enforced.

• allow-nothing Policy: An ALLOW policy that doesn't match anything results in requests being denied by default if no other ALLOW policies exist.
• deny-all Policy: A DENY policy that matches everything denies all requests, even if there is an ALLOW policy.
• allow-all Policy: An ALLOW policy that matches everything allows full access, making other ALLOW policies redundant; however, DENY policies still take precedence.

The when section in authorization policies allows you to specify additional conditions for authorization. This enables fine-grained control based on various attributes.

• Istio Attributes: Leverage Istio attributes to define conditions. For example, you can allow access based on specific request headers or JWT claims.
• Request Headers: You can create custom conditions based on request headers. This lets you control access based on the presence or value of specific headers.
• JWT Claims: You can also create conditions based on JWT claims. This is useful for enforcing access control based on user roles or permissions encoded in the JWT.

With these advanced configurations, you can significantly enhance the security and flexibility of your service mesh.

Next, we will cover best practices for securing Non-Human Identities (NHIs) within the service mesh.

Best Practices for Implementing Service Mesh Authorization

Is your service mesh strategy as strong as it could be? Let's examine some key steps to make your implementation robust and secure.

A crucial first step in securing your service mesh is proper service account management. A Kubernetes service account provides an identity for processes that run in a Pod.

• Create a Kubernetes service account for each service. This provides a unique identity for every service within your cluster.
• Specify the service account in the Deployment configuration. This links the service account to the workload, associating the workload with its unique identity.
• This practice enhances identity and simplifies authorization policy configuration. As noted earlier, Non-Human Identities are critical for effective authorization, so using service accounts makes it easier to manage these identities.

Applying the principle of least privilege is a fundamental security practice. This involves granting each service only the minimum necessary permissions to perform its intended function.

• Start with an allow-nothing policy and incrementally add more ALLOW policies. This ensures that no unintended access is granted by default.
• Grant only the necessary permissions to each workload. For example, a payment service should only be allowed to access the billing service's charge endpoint.
• Following the principle of least privilege reduces the risk of unauthorized access and lateral movement. If a service is compromised, the attacker's access is limited to only the explicitly granted permissions.

If your services rely on JSON Web Tokens (JWT) for authentication, specific steps can help secure them. JWTs are a standard for securely transmitting information between parties as a JSON object.

• Create a DENY policy to block unauthenticated requests.
• Apply an allow-nothing policy. This is a baseline that denies all requests that do not meet specific criteria.
• Define ALLOW policies for each workload based on JWT claims. Configure your authorization policies to validate the JWT’s issuer, audience, and other relevant claims.

By implementing these best practices, you can significantly enhance the security of your service mesh. These steps ensure that access is controlled, authenticated, and authorized based on well-defined policies.

Next, we'll explore how to monitor and audit your service mesh to continuously improve its security posture.

Leveraging Non-Human Identity Management Group for Enhanced Security

Is managing Non-Human Identities (NHIs) keeping you up at night? Securing service meshes requires specialized expertise, and that's where a dedicated partner can make all the difference.

NHIMG is the leading independent authority in NHI Research and Advisory. We empower organizations to tackle the critical risks of Non-Human Identities (NHIs). Our focus is on helping you understand and secure your service mesh.

Stay updated on the ever-changing landscape of Non-Human Identities with NHIMG's research. Our advisory services can help you implement robust authorization policies and secure your service mesh.

NHIMG specializes in providing comprehensive non-human identity management solutions. Our offerings include:

• NHI Strategy Development: We help you develop a tailored strategy for securing service meshes. This includes identifying critical NHIs and mapping out your authorization policies.
• Expert Guidance: NHIMG offers expert guidance on implementing authorization policies within service meshes. We ensure your policies align with industry best practices.
• Security Posture Assessment: NHIMG provides assessment of your current security posture and recommendations for improvement. We help you identify vulnerabilities related to NHIs.

Ready to take the next step in securing your service mesh? Here's how NHIMG can help:

• Contact NHIMG for a consultation to discuss your specific service mesh security needs. We'll assess your current setup and identify areas for improvement.
• Leverage NHIMG's expertise to design and implement robust authorization policies. Our team will help you create policies that effectively manage NHI access.
• Enhance your overall security posture with NHIMG's comprehensive NHI management solutions. We provide ongoing support and guidance to keep your service mesh secure.

By partnering with NHIMG, you can ensure your service mesh is protected against unauthorized access and potential threats. In the next section, we'll explore how to monitor and audit your service mesh.

Conclusion: Securing Your Service Mesh with Confidence

Securing your service mesh might seem daunting, but with the right approach, you can achieve a robust security posture. Let's recap the key concepts and chart a path forward.

• Service mesh authorization policies are essential for controlling access between microservices. This ensures that only authenticated and authorized Non-Human Identities (NHIs) can communicate with each other.

• NHIs play a critical role in service-to-service access control, as mentioned earlier. Properly managing these identities is paramount for maintaining a secure environment.

• Properly configured authorization policies mitigate both insider and external threats. This protects sensitive data and prevents unauthorized access to critical resources.

• Expect continued evolution of service mesh security features. The need to protect workloads is ever present, and these features will adapt to meet those needs.

• We will also see tighter integration with other security tools and platforms. This will provide a more holistic approach to security.

• It is important to stay informed about the latest security best practices. Continuous learning will ensure you are prepared for the next threats.

• Review your current service mesh security configuration. Identify any gaps or areas for improvement.

• Implement authorization policies based on the principle of least privilege. Grant only the necessary permissions to each workload.

• Continuously monitor and update your security policies. Adapt to evolving threats and vulnerabilities.

With these steps, you can confidently secure your service mesh and protect your microservices.