Securing APIs with Azure API Management OAuth 2.0 authentication

Question

Pulumi · Accepted Answer

Securing APIs using OAuth 2.0 in Azure API Management involves several steps:

Create an Azure API Management Service: This is the central point through which API traffic is managed and secured. It allows you to define APIs, set up policies for transformation and control, and monitor traffic.
Configure an Identity Provider: This is where you set up the OAuth 2.0 authentication, using either Azure Active Directory or an external identity provider for securing your APIs.
Define an OAuth 2.0 Authorization Server: The OAuth server is responsible for generating tokens that clients can use to authenticate API requests.
Set up a Policy: Policies in Azure API Management define the behaviors and transformations that apply to the API requests and responses. For securing APIs, a policy would be used to validate the OAuth tokens with each request.

Here's a Pulumi TypeScript program that demonstrates how to set up an API Management Service with OAuth 2.0 authentication using Azure Active Directory as the identity provider. This code assumes you already have an Azure Active Directory application with a client ID and secret and have the required permissions to create resources in Azure.

import * as azure from "@pulumi/azure-native";

// Create an API Management service instance
const apiManagementService = new azure.apimanagement.ApiManagementService("apiManagementService", {
    // Provide the required information for your Azure subscription and resource group
    resourceGroupName: "your-azure-resource-group-name",
    serviceName: "your-apim-service-name",
    sku: {
        name: "Developer",
        capacity: 1,
    },
    publisherName: "your-publisher-name",
    publisherEmail: "your-publisher-email@example.com",
    // Replace 'your-location' with the Azure region you want to deploy the service in
    location: "your-location",
});

// Configure Azure AD as an identity provider for API Management
const apiManagementIdentityProviderAad = new azure.apimanagement.IdentityProviderAad("apiManagementIdentityProviderAad", {
    // Provide the required information for the identity provider configuration
    clientId: "your-azure-ad-application-client-id",
    clientSecret: "your-azure-ad-application-client-secret",
    signinTenant: "your-azure-ad-tenant-id",
    allowedTenants: ["your-azure-ad-tenant-id"],
    apiManagementName: apiManagementService.name,
    resourceGroupName: "your-azure-resource-group-name",
});

// Define an OAuth 2.0 authorization server in API Management
const oAuthServer = new azure.native.apimanagement.AuthorizationServer("authorizationServer", {
    // Customize the OAuth server configuration to meet your requirements
    displayName: "OAuth2AuthServer",
    clientId: "your-azure-ad-application-client-id",
    clientSecret: "your-azure-ad-application-client-secret",
    grantTypes: ["authorizationCode", "implicit", "clientCredentials"],
    authorizationEndpoint: "https://login.microsoftonline.com/your-azure-ad-tenant-id/oauth2/authorize",
    tokenEndpoint: "https://login.microsoftonline.com/your-azure-ad-tenant-id/oauth2/token",
    // The API Management service that OAuth server is associated with
    serviceName: apiManagementService.name,
    resourceGroupName: "your-azure-resource-group-name",
});

// Apply OAuth 2.0 validation policy for the API
const apiOAuth2ValidationPolicy = new azure.native.apimanagement.Policy("apiOAuth2ValidationPolicy", {
    // Basic policy to validate OAuth 2.0 tokens on the incoming request
    value: `<!-- Policy definition goes here -->
    <inbound>
        <base />
        <validate-jwt header-name="Authorization" failed-validation-httpcode="401" failed-validation-error-message="Unauthorized. Access token is missing or invalid.">
            <openid-config url="https://login.microsoftonline.com/your-azure-ad-tenant-id/.well-known/openid-configuration" />
            <required-claims>
                <claim name="aud">
                    <!-- Your specific validation rules -->
                    <value>your-audience</value>
                </claim>
            </required-claims>
        </validate-jwt>
    </inbound>`,
    format: "xml",
    apiManagementName: apiManagementService.name,
    resourceGroupName: "your-azure-resource-group-name",
});

What this code does:

Initializes a new instance of the Azure API Management service, which is where all API resources and policies are handled.
Sets up Azure Active Directory as an identity provider by creating an IdentityProviderAad instance.
Creates an AuthorizationServer resource that is used by the API Management to issue OAuth2 tokens and validate them against the Azure AD tenant.
Defines an inbound policy for your APIs that validates incoming OAuth tokens to ensure that they are authentic and have the necessary claims to access your APIs.

Please ensure that you replace placeholder values (like your-azure-resource-group-name, your-apim-service-name, etc.) with actual values from your environment. Also, you will need to replace the policy value with actual rules and conditions that apply to your scenario. This policy example above does basic token validation and needs to be expanded with actual claim checks and values that match your OAuth 2.0 setup.

your-audience

`, format: "xml", apiManagementName: apiManagementService.name, resourceGroupName: "your-azure-resource-group-name", }); ``` What this code does: - Initializes a new instance of the Azure API Management service, which is where all API resources and policies are handled. - Sets up Azure Active Directory as an identity provider by creating an `IdentityProviderAad` instance. - Creates an `AuthorizationServer` resource that is used by the API Management to issue OAuth2 tokens and validate them against the Azure AD tenant. - Defines an inbound policy for your APIs that validates incoming OAuth tokens to ensure that they are authentic and have the necessary claims to access your APIs. Please ensure that you replace placeholder values (like `your-azure-resource-group-name`, `your-apim-service-name`, etc.) with actual values from your environment. Also, you will need to replace the policy value with actual rules and conditions that apply to your scenario. This policy example above does basic token validation and needs to be expanded with actual claim checks and values that match your OAuth 2.0 setup.