Azure Event Grid Authentication Methods and Security

Azure Event Grid offers two primary authentication methods: Azure Active Directory (AAD) and Shared Access Signature (SAS).

AAD provides a more secure and scalable solution, allowing for centralized management of identities and access control.

Event Grid also supports the use of SAS tokens, which are a type of token that can be used to authenticate and authorize access to Event Grid resources.

AAD authentication uses OAuth 2.0 and OpenID Connect to authenticate and authorize access to Event Grid resources.

A fresh viewpoint: Eventgrid Azure

Azure Event Grid uses different authentication methods to deliver events to event handlers. Three types of authentication are available: Event subscriptions, Event publishing, and Webhook event delivery.

Event subscriptions require the Microsoft.EventGrid/EventSubscriptions/Write permission on the required resource, which can be a system topic or a custom topic. For system topics, the permission is required to write a new event subscription at the scope of the resource publishing the event.

Worth a look: Event Grid Topic Azure

Event publishing takes advantage of either secret keys or Shared Access Signatures (SAS), which provides more fine-grained control. However, SAS is not fully supported by all webhook systems.

To enforce authentication for event publishing, you need to provide the appropriate HTTP header value, which can be an aeg-sas-token for SAS authentication or an aeg-sas-key for key authentication. The topic key can be grabbed from the portal or by running a command in the Azure CLI or Azure Cloud Shell.

Azure Event Grid also uses a handshake to validate the webhook subscription when first registering a webhook against a topic. If the application doesn't respond by echoing back the validation code, the subscription will fail. To harden security, your application could implement key authentication by including the authentication key in the query string of the HTTP URL endpoint.

You might enjoy: Sas in Azure

Azure Event Grid uses different authentication methods to deliver events to event handlers.

There are multiple authentication methods available, including access key, managed system identity, role-based access control, bearer token authentication with Microsoft Entra protected webhook, and client secret as a query parameter.

Discover more: Azure Mfa Authentication Methods

Access keys are fetched using Event Grid service principal's credentials and can be used to deliver events to event handlers such as Event Hubs, Service Bus, Storage Queues, Relay Hybrid Connections, Azure Functions, and Storage Blobs (Deadletter).

Managed system identity is another option, which enables managed system identity for the topic and adds it to the appropriate role on the destination. This can be used for event handlers such as Event Hubs, Service Bus, Storage Queues, and Storage Blobs (Deadletter).

Here's a summary of the supported event handlers for each authentication method:

Azure Functions can be protected with a Microsoft Entra app, but this requires taking the generic webhook approach using the HTTP trigger.

Event delivery to webhooks is a bit more complex than other authentication methods, but don't worry, it's still straightforward once you understand the process.

To authenticate event delivery to webhook endpoints, you need to use a validation handshake mechanism. This is regardless of the method you use, so make sure to implement this step.

Event Grid uses a POST request to send a validation code to the webhook endpoint. The application needs to respond by echoing back the validation code, or the subscription will fail.

In addition to the validation handshake, you can also implement key authentication to harden security. This involves including your authentication key in the query string when registering a new subscriber endpoint.

Here's a breakdown of the authentication methods supported for event delivery to webhooks:

By implementing these authentication methods, you can ensure secure event delivery to your webhooks and protect against threats like Man-in-the-Middle attacks and Denial of Service attacks.

Azure Event Grid offers two main authentication methods to secure your event delivery: system-assigned identities and Microsoft Entra ID.

You can enable a system-assigned managed identity for a topic or domain and use the identity to forward events to supported destinations. This involves creating a topic or domain with a system-assigned identity, adding the identity to an appropriate role on the destination, and enabling the usage of the identity when creating event subscriptions.

For your interest: Azure Cosmos Db User Assigned Identity

System-assigned identities are a convenient option, but you can also use Microsoft Entra ID to secure your webhook endpoint. This requires creating a Microsoft Entra application, creating a role and a service principal in your application authorizing Event Grid, and configuring the event subscription to use the Microsoft Entra application.

To use Microsoft Entra ID, you need to create a role and a service principal in your application authorizing Event Grid. This step is crucial in securing your webhook endpoint.

Here's a comparison of the two authentication methods:

Webhook Delivery is a crucial aspect of Azure Event Grid authentication. You need to authenticate event delivery to webhook endpoints.

Regardless of the method you choose, use a validation handshake mechanism to ensure secure delivery. This is a best practice for all webhook event delivery.

A validation handshake mechanism is essential for authenticating event delivery to webhook endpoints. This ensures that only authorized endpoints receive events.

You can find more details on webhook event delivery by following the link provided in the relevant article section.

You can secure your webhook endpoint by adding query parameters to the webhook destination URL, including a client secret such as an access token or a shared secret.

Event Grid service includes all query parameters in every event delivery request to the webhook, which the webhook service can then retrieve and validate. If the client secret is updated, the event subscription also needs to be updated.

Azure Event Grid only supports HTTPS webhook endpoints, so make sure to use a secure connection when sending events.

To avoid delivery failures during secret rotation, the webhook should accept both old and new secrets for a limited duration before updating the event subscription with the new secret.

Here's an interesting read: Azure Secure Hub

You can add client secret as a query parameter to the webhook destination URL to secure your endpoint.

Azure Event Grid includes all query parameters in every event delivery request, allowing the webhook service to retrieve and validate the secret.

Client secrets are handled with extra care and are stored as encrypted, making them inaccessible to service operators.

They're not logged as part of the service logs/traces, ensuring an extra layer of security.

To retrieve the Event Subscription properties, including destination query parameters, use the --include-full-endpoint-url parameter in the Azure CLI.

Azure Event Grid only supports HTTPS webhook endpoints, making it essential to use a secure connection when sending client secrets as query parameters.

If the client secret is updated, the event subscription also needs to be updated to avoid delivery failures during the secret rotation process.

For your interest: Azure Keyvault Secrets

Using a SAS Token is a viable option for client authentication. A SAS token is similar to an access key, but it has an expiration time after which it's no longer valid.

A SAS token can be generated by using the generateSharedAccessSigniture function.

To use a SAS token for authentication, you'll need to use the AzureSASCredential.

See what others are reading: Azure Authentication vs Exchange Token Authentication

Azure Event Grid provides three types of authentication: Event subscriptions, Event publishing, and Webhook event delivery. To create a subscription to an event, users need to have the Microsoft.EventGrid/EventSubscriptions/Write permission on the required resource.

To authenticate Event publishing, you can use either secret keys or Shared Access Signatures (SAS). SAS provides more fine-grained control and can be easily revoked, but it's not fully supported by all webhook systems. If the subscriber can't leverage SAS, then the use of the secret key is recommended.

You can also use Azure Active Directory (AAD) for identity-based authentication of requests. With AAD, you can use role-based access control (RBAC) to grant access to your Azure Event Grid resources to users, groups, or applications. To send events to a topic or domain with a TokenCredential, the authenticated identity should have the "EventGrid Data Sender" role assigned.

Here are the three types of authentication provided by Azure Event Grid:

To use AAD with Azure Event Grid, you can use the DefaultAzureCredential to construct a client which will authenticate using Azure Active Directory.

Azure Active Directory (AAD) provides a secure way to authenticate requests to Azure Event Grid resources. You can use role-based access control (RBAC) to grant access to users, groups, or applications.

To send events to a topic or domain, the authenticated identity must have the "EventGrid Data Sender" role assigned. This ensures that only authorized identities can send events.

You can use the @azure/identity package to seamlessly authorize requests in both development and production environments. This package provides a DefaultAzureCredential class that can authenticate using Azure Active Directory.

To construct a client that authenticates using Azure Active Directory, you can use the DefaultAzureCredential class. This class will automatically detect and use the most suitable credential type for your environment.

Here's a summary of the steps to use Azure Active Directory with Azure Event Grid:

To use an Access Key, you can browse to your Event Grid resource in the Azure Portal and retrieve one, or use the Azure CLI snippet provided.

Access Keys can be used until they are regenerated, but be aware that they have no expiration time.

You can authenticate the client using the AzureKeyCredential class once you have an API key and endpoint.

Using an Access Key is a straightforward process, but it's essential to keep track of your keys to avoid any issues.

Access Keys can be used to send events to an Event Grid topic, but it's crucial to note that they can be used until they are regenerated, unlike SAS tokens which have an expiration time.

Here's an interesting read: Access Azure Key Vault Using Service Principal C#

Security and Event Grid is a crucial aspect of Azure Event Grid. It provides three types of authentication: Event subscriptions, Event publishing, and Webhook event delivery.

To securely subscribe to events, you need to have the Microsoft.EventGrid/EventSubscriptions/Write permission on the required resource. This permission allows you to write a new event subscription at the scope of the resource publishing the event.

Consider reading: Azure Event Hub vs Event Grid

Event publishing takes advantage of either secret keys or Shared Access Signatures (SAS), which provides more fine-grained control. However, SAS is not fully supported by all webhook systems.

To enforce authentication, you need to provide the appropriate HTTP header value. For SAS authentication, you need to use an aeg-sas-token, while for key authentication, you need to use an aeg-sas-key.

Azure Event Grid uses a handshake mechanism to validate webhook subscriptions. It sends a POST request with a validation code to prove that you own the endpoint. If the application doesn't respond by echoing back the validation code, the subscription will fail.

To harden security, you can implement key authentication by including your authentication key in the query string of the webhook endpoint URL. This eliminates the Man in the Middle (MitM) threat and makes Denial of Service (DoS) attacks harder.

Here are the authentication methods for Event Grid:

You can also secure your webhook endpoint by adding query parameters to the webhook destination URL. Set one of the query parameters to be a client secret, such as an access token or a shared secret. This method is supported by Azure Event Grid.

To create an Event Grid client, you'll need the endpoint of your Event Grid topic, which can be found in the Azure Portal or using the Azure CLI snippet.

You can authenticate the client using either an Access Key or a Shared Access Signature (SAS) created from an access key.

To create a client object to access the Event Grid API, you'll need the endpoint of your Event Grid topic and a credential. You can find the endpoint for your Event Grid topic in the Azure Portal.

The Event Grid client can use either an Access Key or Shared Access Signature (SAS) created from an access key. You can use the Azure CLI to find the endpoint for your Event Grid topic.

To create a client object, you'll need a credential. The credential can be an Access Key or a Shared Access Signature (SAS) created from an access key.

You might enjoy: Azure Bitlocker Recovery Key

Email notifications can be a game-changer for keeping track of new subscription accounts. This is especially true for the Event Grid client, which allows you to customize your email notifications.

You can choose to receive an email notification when a new subscription account is created, such as when a new subscription account is created for a specific resource type.

Event Grid supports multiple schemas for encoding events, including the Event Grid schema, CloudEvents 1.0 schema, and Custom Event Schema.

To use the Event Grid schema, you need to set "EventGrid" as the schema type when constructing the EventGridPublisherClient.

You can configure your topic to use a custom schema, but it's more common to use the already defined Event Grid schema or CloudEvents 1.0 schema.

If your topic is configured to use the Cloud Event Schema, set "CloudEvent" as the schema type when constructing the client.

Constructing the client with a different schema than what the topic is configured to expect will result in an error from the service and your events will not be published.

You can see what input schema has been configured for an Event Grid topic by using the Azure CLI snippet below: npm i @azure/eventgrid.

Take a look at this: Azure Events