All posts by Abhishek Panday

Use Amazon Verified Permissions for fine-grained authorization at scale

Post Syndicated from Abhishek Panday original https://aws.amazon.com/blogs/security/use-amazon-verified-permissions-for-fine-grained-authorization-at-scale/

Implementing user authentication and authorization for custom applications requires significant effort. For authentication, customers often use an external identity provider (IdP) such as Amazon Cognito. Yet, authorization logic is typically implemented in code. This code can be prone to errors, especially as permissions models become complex, and presents significant challenges when auditing permissions and deciding who has access to what. As a result, within Common Weakness Enumeration’s (CWE’s) list of the Top 25 Most Dangerous Software Weaknesses for 2023, four are related to incorrect authorization.

At re:Inforce 2023, we launched Amazon Verified Permissions, a fine-grained permissions management service for the applications you build. Verified Permissions centralizes permissions in a policy store and lets developers use those permissions to authorize user actions within their applications. Permissions are expressed as Cedar policies. You can learn more about the benefits of moving your permissions centrally and expressing them as policies in Policy-based access control in application development with Amazon Verified Permissions.

In this post, we explore how you can provide a faster and richer user experience while still authorizing all requests in the application. You will learn two techniques—bulk authorization and response caching—to improve the efficiency of your applications. We describe how you can apply these techniques when listing authorized resources and actions and loading multiple components on webpages.

Use cases

You can use Verified Permissions to enforce permissions that determine what the user is able to see at the level of the user interface (UI), and what the user is permitted to do at the level of the API.

  1. UI permissions enable developers to control what a user is allowed see in the application. Developers enforce permissions in the UI to control the list of resources a user can see and the actions they can take. For example, a UI-level permission in a banking application might determine whether a transfer funds button is enabled for a given account.
  2. API permissions enable developers to control what a user is allowed to do in an application. Developers control access to individual API calls made by an application on behalf of the user. For example, an API-level permission in a banking application might determine whether a user is permitted to initiate a funds transfer from an account.

Cedar provides consistent and readable policies that can be used at both the level of the UI and the API. For example, a single policy can be checked at the level of the UI to determine whether to show the transfer funds button and checked at the level of the API to determine authority to initiate the funds transfer.

Challenges

Verified Permissions can be used for implementing fine-grained API permissions. Customer applications can use Verified Permissions to authorize API requests, based on centrally managed Cedar policies, with low latency. Applications authorize such requests by calling the IsAuthorized API of the service, and the response contains whether the request is allowed or denied. Customers are happy with the latency of individual authorization requests, but have asked us to help them improve performance for use cases that require multiple authorization requests. They typically mention two use cases:

  • Compound authorization: Compound authorization is needed when one high-level API action involves many low-level actions, each of which has its own permissions. This requires the application to make multiple requests to Verified Permissions to authorize the user action. For example, in a banking application, loading a credit card statement requires three API calls: GetCreditCardDetails, GetCurrentStatement, and GetCreditLimit. This requires three calls to Verified Permissions, one for each API call.
  • UI permissions: Developers implement UI permissions by calling the same authorization API for every possible resource a principal can access. Each request involves an API call, and the UI can only be presented after all of them have completed. Alternatively, for a resource-centric view, the application can make the call for multiple principals to determine which ones have access.

Solution

In this post, we show you two techniques to optimize the application’s latency based on API permissions and UI permissions.

  1. Batch authorization allows you to make up to 30 authorization decisions in a single API call. This feature was released in November 2023. See the what’s new post and API specifications to learn more.
  2. Response caching enables you to cache authorization responses in a policy enforcement point such as Amazon API Gateway, AWS AppSync, or AWS Lambda. You can cache responses using native enforcement point caches (for example, API Gateway caching) or managed caching services such as Amazon ElastiCache.

Solving for enforcing fine grained permissions while delivering a great user experience

You can use UI permissions to authorize what resources and actions a user can view in an application. We see developers implementing these controls by first generating a small set of resources based on database filters and then further reducing the set down to authorized resources by checking permissions on each resource using Verified Permissions. For example, when a user of a business banking system tries to view balances on company bank accounts, the application first filters the list to the set of bank accounts for that company. The application then filters the list further to only include the accounts that the user is authorized to view by making an API request to Verified Permissions for each account in the list. With batch authorization, the application can make a single API call to Verified Permissions to filter the list down to the authorized accounts.

Similarly, you can use UI permissions to determine what components of a page or actions should be visible to users of the application. For example, in a banking application, the application wants to control the sub-products (such as credit card, bank account, or stock trading) visible to a user or only display authorized actions (such as transfer or change address) when displaying an account overview page. Customers want to use Verified Permissions to determine which components of the page to display, but that can adversely impact the user experience (UX) if they make multiple API calls to build the page. With batch authorization, you can make one call to Verified Permissions to determine permissions for all components of the page. This enables you to provide a richer experience in your applications by displaying only the components that the user is allowed to access while maintaining low page load latency.

Solving for enforcing permissions for every API call without impacting performance

Compound authorization is where a single user action results in a sequence of multiple authorization calls. You can use bulk authorization combined with response caching to improve efficiency. The application makes a single bulk authorization request to Verified Permissions to determine whether each of the component API calls are permitted and the response is cached. This cache is then referenced for each component’s API call in the sequence.

Sample application – Use cases, personas, and permissions

We’re using an online order management application for a toy store to demonstrate how you can apply batch authorization and response caching to improve UX and application performance.

One function of the application is to enable employees in a store to process online orders.

Personas

The application is used by two types of users:

  • Pack associates are responsible for picking, packing, and shipping orders. They’re assigned to a specific department.
  • Store managers are responsible for overseeing the operations of a store.

Use cases

The application supports these use cases:

  1. Listing orders: Users can list orders. A user should only see the orders for which they have view permissions.
    • Pack associates can list all orders of their department.
    • Store managers can list all orders of their store.

    Figure 1 shows orders for Julian, who is a pack associate in the Soft Toy department

    Figure 1: Orders for Julian in the Soft Toy department

    Figure 1: Orders for Julian in the Soft Toy department

  2. Order actions: Users can take some actions on an order. The application enables the relevant UI elements based on the user’s permissions.
    • Pack associates can select Get Box Size and Mark as Shipped, as shown in Figure 2.
    • Store managers can select Get Box Size, Mark as Shipped, Cancel Order, and Route to different warehouse.
    Figure 2: Actions available to Julian as a pack associate

    Figure 2: Actions available to Julian as a pack associate

  3. Viewing an order: Users can view the details of a specific order. When a user views an order, the application loads the details, label, and receipt. Figure 3 shows the available actions for Julian who is a pack associate.
    Figure 3: Order Details for Julian, showing permitted actions

    Figure 3: Order Details for Julian, showing permitted actions

Policy design

The application uses Verified Permissions as a centralized policy store. These policies are expressed in Cedar. The application uses the Role management using policy templates approach for implementing role-based access controls. We encourage you to read best practices for using role-based access control in Cedar to understand if the approach fits your use case.

In the sample application, the policy template for the store owner role looks like the following:

permit (
        principal == ?principal,
        action in [
                avp::sample::toy::store::Action::"OrderActions",
                avp::sample::toy::store::Action::"AddPackAssociate",
                avp::sample::toy::store::Action::"AddStoreManager",
                avp::sample::toy::store::Action::"ListPackAssociates",
                avp::sample::toy::store::Action::"ListStoreManagers"
        ],
        resource in ?resource
);

When a user is assigned a role, the application creates a policy from the corresponding template by passing the user and store. For example, the policy created for the store owner is as follows:

permit (
    principal ==  avp::sample::toy::store::User::"test_user_pool|sub_store_manager_user", 
    action in  [
                avp::sample::toy::store::Action::"OrderActions",
                avp::sample::toy::store::Action::"AddPackAssociate",
                avp::sample::toy::store::Action::"AddStoreManager",
                avp::sample::toy::store::Action::"ListPackAssociates",
                avp::sample::toy::store::Action::"ListStoreManagers"
    ],
    resource in avp::sample::toy::store::Store::"toy store 1"
);

To learn more about the policy design of this application, see the readme file of the application.

Use cases – Design and implementation

In this section, we discuss high level design, challenges with the barebones integration, and how you can use the preceding techniques to reduce latency and costs.

Listing orders

Figure 4: Architecture for listing orders

Figure 4: Architecture for listing orders

As shown in Figure 4, the process to list orders is:

  1. The user accesses the application hosted in AWS Amplify.
  2. The user then authenticates through Amazon Cognito and obtains an identity token.
  3. The application uses Amplify to load the order page. The console calls the API ListOrders to load the order.
  4. The API is hosted in API Gateway and protected by a Lambda authorizer function.
  5. The Lambda function collects entity information from an in-memory data store to formulate the isAuthorized request.
  6. Then the Lambda function invokes Verified Permissions to authorize the request. The function checks against Verified Permissions for each order in the data store for the ListOrder call. If Verified Permissions returns deny, the order is not provided to the user. If Verified Permissions returns allow, the request is moved forward.

Challenge

Figure 5 shows that the application called IsAuthorized multiple times, sequentially. Multiple sequential calls cause the page to be slow to load and increase infrastructure costs.

Figure 5: Graph showing repeated calls to IsAuthorized

Figure 5: Graph showing repeated calls to IsAuthorized

Reduce latency using batch authorization

If you transition to using batch authorization, the application can receive 30 authorization decisions with a single API call to Verified Permissions. As you can see in Figure 6, the time to authorize has reduced from close to 800 ms to 79 ms, delivering a better overall user experience.

Figure 6: Reduced latency by using batch authorization

Figure 6: Reduced latency by using batch authorization

Order actions

Figure 7: Order actions architecture

Figure 7: Order actions architecture

As shown in Figure 7, the process to get authorized actions for an order is:

  1. The user goes to the application landing page on Amplify.
  2. The application calls the Order actions API at API Gateway
  3. The application sends a request to initiate order actions to display only authorized actions to the user.
  4. The Lambda function collects entity information from an in-memory data store to formulate the isAuthorized request.
  5. The Lambda function then checks with Verified Permissions for each order action. If Verified Permissions returns deny, the action is dropped. If Verified Permissions returns allow, the request is moved forward and the action is added to a list of order actions to be sent in a follow-up request to Verified Permissions to provide the actions in the user’s UI.

Challenge

As you saw with listing orders, Figure 8 shows how the application is still calling IsAuthorized multiple times, sequentially. This means the page remains slow to load and has increased impacts on infrastructure costs.

Figure 8: Graph showing repeated calls to IsAuthorized

Figure 8: Graph showing repeated calls to IsAuthorized

Reduce latency using batch authorization

If you add another layer by transitioning to using batch authorization once again, the application can receive all decisions with a single API call to Verified Permissions. As you can see from Figure 9, the time to authorize has reduced from close to 500 ms to 150 ms, delivering an improved user experience.

Figure 9: Graph showing results of layering batch authorization

Figure 9: Graph showing results of layering batch authorization

Viewing an order

Figure 10: Order viewing architecture

Figure 10: Order viewing architecture

The process to view an order, shown in Figure 10, is:

  1. The user accesses the application hosted in Amplify.
  2. The user authenticates through Amazon Cognito and obtains an identity token.
  3. The application calls three APIs hosted at API Gateway.
  4. The API’s: Get order details, Get label, and Get receipt are targeted sequentially to load the UI for the user in the application.
  5. A Lambda authorizer protects each of the above-mentioned APIs and is launched for each invoke.
  6. The Lambda function collects entity information from an in-memory data store to formulate the isAuthorized request.
  7. For each API, the following steps are repeated. The Lambda authorizer is invoked three times during page load.
    1. The Lambda function invokes Verified Permissions to authorize the request. If Verified Permissions returns deny, the request is rejected and an HTTP unauthorized response (403) is sent back. If Verified Permissions returns allow, the request is moved forward. 
    2. If the request is allowed, API Gateway calls the Lambda Order Management function to process the request. This is the primary Lambda function supporting the application and typically contains the core business logic of the application.

Challenge

In using the standard authorization pattern for this use case, the application calls Verified Permissions three times. This is because the user action to view an order requires compound authorization because each API call made by the console is authorized. While this enforces least privilege, it impacts the page load and reload latency of the application.

Reduce latency using batch authorization and decision caching

You can use batch authorization and decision caching to reduce latency. In the sample application, the cache is maintained by API Gateway. As shown in Figure 11, applying these techniques to the console application results in only one call to Verified Permissions, reducing latency.

Figure 11: Batch authorization with decision caching architecture

Figure 11: Batch authorization with decision caching architecture

The decision caching processshown in Figure 11, is:

  1. The user accesses the application hosted in Amplify.
  2. The user then authenticates through Amazon Cognito and obtains an identity token.
  3. The application then calls three APIs hosted at API Gateway
  4. When the Lambda function for the Get order details API is invoked, it uses the Lambda Authorizer to call batch authorization to get authorization decisions for the requested action, Get order details, and related actions, Get label and Get receipt.
  5. A Lambda authorizer protects each of the above-mentioned APIs but because of batch authorization, is invoked only once.
  6. The Lambda function collects entity information from an in-memory data store to formulate the isAuthorized request.
  7. The Lambda function invokes Verified Permissions to authorize the request. If Verified Permissions returns deny, the request is rejected and an HTTP unauthorized response (403) is sent back. If Verified Permissions returns allow, the request is moved forward.
    1. API Gateway caches the authorization decision for all actions (the requested action and related actions).
    2. If the request is allowed by the Lambda authorizer function, API Gateway calls the order management Lambda function to process the request. This is the primary Lambda function supporting the application and typically contains the core business logic of the application.
    3. When subsequent APIs are called, the API Gateway uses the cached authorization decisions and doesn’t use the Lambda authorization function.

Caching considerations

You’ve seen how you can use caching to implement fine-grained authorization at scale in your applications. This technique works well when your application has high cache hit rates, where authorization results are frequently loaded from the cache. Applications where the users initiate the same action multiple times or have a predictable sequence of actions will observe high cache hit rates. Another consideration is that employing caching can delay the time between policy updates and policy enforcement. We don’t recommend using caching for authorization decisions if your application requires policies to take effect quickly or your policies are time dependent (for example, a policy that gives access between 10:00 AM and 2:00 PM).

Conclusion

In this post, we showed you how to implement fine grained permissions in application at scale using Verified Permissions. We covered how you can use batch authorization and decision caching to improve performance and ensure Verified Permissions remains a cost-effective solution for large-scale applications. We applied these techniques to a demo application, avp-toy-store-sample, that is available to you for hands-on testing. For more information about Verified Permissions, see the Amazon Verified Permissions product details and Resources.

 
If you have feedback about this post, submit comments in the Comments section below. If you have questions about this post, contact AWS Support.

Abhishek Panday

Abhishek Panday

Abhishek is a product manager in the Amazon Verified Permissions team. He’s been working with AWS for more than two years and has been at Amazon for over five years. Abhishek enjoys working with customers to understand their challenges and building products to solve those challenges. Abhishek currently lives in Seattle and enjoys playing soccer, hiking, and cooking Indian cuisines.

Jeremy Wave

Jeremy Ware

Jeremy is a Security Specialist Solutions Architect focused on Identity and Access Management. Jeremy and his team enable AWS customers to implement sophisticated, scalable, and secure architectures to solve business challenges. Jeremy has spent many years working to improve the security maturity at numerous global enterprises. In his free time, Jeremy loves to enjoy the outdoors with his family.

Manage roles and entitlements with PBAC using Amazon Verified Permissions

Post Syndicated from Abhishek Panday original https://aws.amazon.com/blogs/devops/manage-roles-and-entitlements-with-pbac-using-amazon-verified-permissions/

Traditionally, customers have used role-based access control (RBAC) to manage entitlements within their applications. The application controls what users can do, based on the roles they are assigned. But, the drive for least privilege has led to an exponential growth in the number of roles. Customers can address this role explosion by moving authorization logic out of the application code, and implementing a policy-based access control (PBAC) model that augments RBAC with attribute-based access control (ABAC).

In this blog post, we cover roles and entitlements, how they are applicable in apps authorization decisions, how customers implement roles and authorization in their app today, and how to shift to a centralized PBAC model by using Amazon Verified Permissions.

Describing roles and entitlements, approaches and challenges of current implementations

In RBAC models, a user’s entitlements are assigned based on job role. This role could be that of a developer, which might grant permissions to affect code in the pipeline of an app. Entitlements represent the features, functions, and resources a user has permissions to access. For example, a customer might be able to place orders or view pets in a pet store application, or a store owner might be entitled to review orders made from their store.

The combination of roles assigned to a user and entitlements granted to these roles determines what a human user can do within your application. Traditionally, application access has all been handled in code by hard coding roles that users can be assigned and mapping those roles directly to a set of actions on resources. However, as the need to apply more granular access control grows (as with least privilege), so do the number of required hard-coded roles that are assigned to users to obtain this level of granularity. This problem is frequently called role explosion, where role definitions grow exponentially which requires additional overhead from your teams to manage and audit roles effectively. For example, the code to authorize request to get details of an order has multiple if/else statements, as shown in the following sample.


boolean userAuthorizedForOrder (Order order, User user){
    if (user.storeId == user.storeID) {
        if (user.roles.contains("store-owner-roles") {            // store owners can only access orders for their own stores  
            return true; 
        } else if (user.roles.contains("store-employee")) {
            if (isStoreOpen(current_time)) {                      // Only allow access for the order to store-employees when
                return true                                       // store is open 
            }
        }
    } else {
        if (user.roles("customer-service-associate") &&           // Only allow customer service associates to orders for cases 
                user.assignedShift(current_time)) &&              // they are assinged and only during their assigned shift
                user.currentCase.order.orderId == order.orderId
         return true;
    }
    return false; 
}

This problem introduces several challenges. First, figuring out why a permission was granted or denied requires a closer look at the code. Second, adding a permission requires code changes. Third, audits can be difficult because you either have to run a battery of tests or explore code across multiple files to demonstrate access controls to auditors. Though there might be additional considerations, these three challenges have led many app owners to begin looking at PBAC methods to address the granularity problem. You can read more about the foundations of PBAC models in Policy-based access control in application development with Amazon Verified Permissions. By shifting to a PBAC model, you can reduce role growth to meet your fine-grained permissions needs. You can also externalize authorization logic from code, develop granular permissions based on roles and attributes, and reduce the time that you spend refactoring code for changes to authorization decisions or reading through the code to audit authorization logic.

In this blog, we demonstrate implementing permissions in a PBAC model through a demo application. The demo application uses Cognito groups to manage role assignment, Verified Permissions to implement entitlements for the roles. The approach restricts the resources that a role can access using attribute-based conditions. This approach works well in usecases when you already have a system in place to manage role assignment and you can define resources that a user may access by matching attributes of the user with attributes of the resource.

Demo app

Let’s look at a sample pet store app. The app is used by 2 types of users – end users and store owners. The app enables end users to search and order pets. The app allows store owners to list orders for the store. This sample app is available for download and local testing on the aws-samples/avp-petstore-sample Github repository. The app is a web app built by using AWS Amplify, Amazon API-Gateway, Amazon Cognito, and Amazon Verified Permissions. The following diagram is a high-level illustration of the app’s architecture.

Architectural Diagram

Steps

  1. The user logs in to the application, and is re-directed to Amazon Cognito to sign-in and obtain a JWT token.
  2. When user take an action (eg. ListOrders) in the application, the application calls Amazon API-Gateway to process the request.
  3. Amazon API-Gateway forwards the request to a lambda function, that call Amazon Verified Permissions to authorize the action. If the authorization results in deny, the lambda returns Unauthorized back to the application.
  4. If the authorization succeed, the application continues to execute the action.

RBAC policies in action

In this section, we focus on building RBAC permissions for the sample pet store app. We will guide you through building RBAC by using Verified Permissions and by focusing on a role for store owners, who are allowed to view all orders for a store. We use Verified Permissions to manage the permissions granted to this role and Amazon Cognito to manage role assignments.

We model the store owner role in Amazon Cognito as a user group called Store-Owner-Role. When a user is assigned the store owner role, the user is added to the “Store-Owner-Role” user group. You can create the users and users groups required to follow along with the sample application by visiting managing users and groups in Amazon Cognito.

After users are assigned to the store owner role, you can enforce that they can list all orders in the store by using the following RBAC policy. The policy provides access to any user in the Store-Owner-Role to perform the ListOrders and GetStoreInventory actions on any resource.

permit (
         principal in MyApplication::Group::"Store-Owner-Role",
         action in [
              MyApplication::Action::"GetStoreInventory",
              MyApplication::Action::"ListOrders"
         ],
         resource
);

Based on the policy we reviewed – the store owner will receive a Success! when they attempt to list existing orders.

Eve is permitted to list orders

This example further demonstrates the division of responsibility between the identity provider (Amazon Cognito) and Verified Permissions. The identity provider (IdP) is responsible for managing roles and memberships in roles. Verified Permissions is responsible for managing policies that describe what those roles are permitted to do. As demonstrated above, you can use this process to add roles without needing to change code.

Using PBAC to help reduce role explosion

Up until the point of role explosion, RBAC has worked well as the sole authorization model. Unfortunately, we have heard from customers that this model does not scale well because of the challenge of role explosion. Role explosion happens when you have hundreds or thousands of roles, and managing and auditing those roles becomes challenging. In extreme cases, you might have more roles than the number of users in your organization. This happens primarily because organizations keep creating more roles, with each role granting access to a smaller set of resources in an effort to follow the principle of least privilege.

Let’s understand the problem of role explosion through our sample pet store app. The pet store app is now being sold as a SaaS product to pet stores in other locations. As a result, the app needs additional access controls to ensure that each store owner can view only the orders from their own store. The most intuitive way to implement these access controls was to create an additional role for each location, which would restrict the scope of access for a store owner to their respective store’s orders. For example, a role named petstore-austin would allow access only to resources in the Austin, Texas store. RBAC models allow developers to predefine sets of permissions that can be used in an application, and ABAC models allow developers to adapt those permissions to the context of the request (such as the client, the resource, and the method used). The adoption of both RBAC and ABAC models leads to an explosion of either roles or attribute-based rules as the number of store locations increases.

To solve this problem, you can combine RBAC and ABAC policies into a PBAC model. RBAC policies determines the actions the user can take. Augmenting these policies with ABAC policies allows you to control the resouces they can take those actions on. For example, you can scope down the resources a user can access based on identity attributes, such as department or business unit, region, and management level. This approach mitigates role explosion because you need to have only a small number of predefined roles, and access is controlled based on attributes. You can use Verified Permissions to combine RBAC and ABAC models in the form of Cedar policies to build this PBAC solution.

We can demonstrate this solution in the sample pet store app by modifying the policy we created earlier and adding ABAC conditions. The conditions specify that users can only ListOrders of the store they own. The store a store owner owns is represented in Amazon Cognito by employmentStoreCode. This policy now expands on the granularity of access of the original RBAC policy without leading to numerous RBAC policies.

permit (
         principal in MyApplication::Group::"Store-Owner-Role",
         action in [
              MyApplication::Action::"GetStoreInventory",
              MyApplication::Action::"ListOrders"
          ],
          resource
) when { 
          principal.employmentStoreCode == resource.storeId 
};

We demonstrate that our policy restricts access for store owners to the store they own, by creating a user – eve – who is assigned the Store-Owner-Role and owns petstore-london. When Eve lists orders for the petstore-london store, she gets a success response, indicating she has permissions to list orders.
Eve is permitted to list orders for petstore-london

Next, when even tries to list orders for the petstore-seattle store, she gets a Not Authorized response. She is denied access as she does not own petstore-seattle.

Eve is not permitted to list orders for petstore-seattle

Step-by-step walkthrough of trying the Demo App

If you want to go through the demo of our sample pet store app, we recommend forking it from aws-samples/avp-petstore-sample Github repo and going through this process in README.md to ensure hands-on familiarity.

We will first walk through setting up permissions using only RBAC for the sample pet store application. Next, we will see how you can use PBAC to implement least priveledge as the application scales.

Implement RBAC based Permissions

We describe setting up policies to implement entitlements for the store owner role in Verified Permissions.

    1. Navigate to the AWS Management Console, search for Verified Permissions, and select the service to go to the service page.
    2. Create new policy store to create a container for your policies. You can create an Empty Policy Store for the purpose of the walk-through.
    3. Navigate to Policies in the navigation pane and choose Create static policy.
    4. Select Next and paste in the following Cedar policy and select Save.
permit (
        principal in MyApplication::Group::"Store-Owner-Role",
        action in [
               MyApplication::Action::"GetStoreInventory",
               MyApplication::Action::"ListOrders"
         ],
         resource
);
  1. You need to get users and assign the Store-Owner-Role to them. In this case, you will use Amazon Cognito as the IdP and the role can be assigned there. You can create users and groups in Cognito by following the below steps.
    1. Navigate to Amazon Cognito from the AWS Management Console, and select the user group created for the pet store app.
    2. Creating a user by clicking create user and create a user with user name eve
    3. Navigate to the Groups section and create a group called Store-Owner-Role .
    4. Add eve to the Store-Owner-Role group by clicking Add user to Group, selecting eve and clicking the Add.
  2. Now that you have assigned the Store-Owner-Role to the user, and Verified Permissions has a permit policy granting entitlements based on role membership, you can log in to the application as the user – eve – to test functionality. When choosing List All Orders, you can see the approval result in the app’s output.

Implement PBAC based Permissions

As the company grows, you want to be able to limit GetOrders access to a specific store location so that you can follow least privilege. You can update your policy to PBAC by adding an ABAC condition to the existing permit policy. You can add a condition in the policy that restricts listing orders to only those stores the user owns.

Below is the walk-though of updating the application

    1. Navigate to the Verified Permissions console and update the policy to the below.
permit (
         principal in MyApplication::Group::"Store-Owner-Role",
         action in [
              MyApplication::Action::"GetStoreInventory",
              MyApplication::Action::"ListOrders"
          ],
          resource
) when { 
          principal.employmentStoreCode == resource.storeId 
};
  1. Navigate to the Amazon Cognito console, select the user eve and click “Edit” in the user attributes section to update the “custom:employmentStoreCode”. Set the attribute value to “petstore-london” as eve owns the petstore-london location
  2. You can demonstrate that eve can only list orders of “petstore-london” by following the below steps
    1. We want to make sure that latest changes to the user attributed are passed to the application in the identity token. We will refresh the identity token, by logging out of the app and logging in again as Eve. Navigate back to the application and logout as eve.
    2. In the application, we set the Pet Store Identifier as petstore-london and click the List All Orders. The result is success!, as Eve is authorized to list orders of the store she owns.
    3. Next, we change the Pet Store Identifier to petstore-seattle and and click the List All Orders. The result is Not Authorized, as Eve is authorized to list orders of stores she does not owns.

Clean Up section

You can cleanup the resources that were created in this blog by following these steps.

Conclusion

In this post, we reviewed what roles and entitlements are as well as how they are used to manage user authorization in your app. We’ve also covered RBAC and ABAC policy examples with respect to the demo application, avp-petstore-sample, that is available to you via AWS Samples for hands-on testing. The walk-through also covered our example architecture using Amazon Cognito as the IdP and Verified Permissions as the centralized policy store that assessed authorization results based on the policies set for the app. By leveraging Verified Permissions, we could use PBAC model to define fine-grained access while preventing role explosion. For more information about Verified Permissions, see the Amazon Verified Permissions product details page and Resources page.

Abhishek Panday

Abhishek is a product manager in the Amazon Verified Permissions team. He has been working with the AWS for more than two years, and has been at Amazon for more than five years. Abhishek enjoys working with customers to understand the customer’s challenges and building products to solve those challenges. Abhishek currently lives in Seattle and enjoys playing soccer, hiking, and cooking Indian cuisines.

Jeremy Ware

Jeremy is a Security Specialist Solutions Architect focused on Identity and Access Management. Jeremy and his team enable AWS customers to implement sophisticated, scalable, and secure IAM architecture and Authentication workflows to solve business challenges. With a background in Security Engineering, Jeremy has spent many years working to raise the Security Maturity gap at numerous global enterprises. Outside of work, Jeremy loves to explore the mountainous outdoors participate in sports such as Snowboarding, Wakeboarding, and Dirt bike riding.