I'm attempting to develop an application architecture almost exclusively on top of AWS services.
This application has both User and Organization "entities". As one might except, a User may be an admin, role-x or role-y of one or more organizations. (role-x and role-y are just placeholders for some role with some set of specific permissions. A User may also be standalone (that is, not have a role on any Organization).
Our current thinking is to use DynamoDB to store organization and user specific data. For users this may include some basic information (address, phone number, whatever), and for organizations it may include fields like "mission statement", "business address" and so on.
An admin of an organization would be able to edit all organization fields, whereas a role-x might only be able to update "mission statement" while reading all other fields.
Since I mentioned that a single user may have roles on many different organizations, that might look something like:
user1:
organizations:
123: 'admin'
456: 'role-x'
789: 'admin'
It's also worth noting that these role assignments are modifiable. New or existing users may be invited to take on a specific role for an organization, and an organization may remove a user from a role.
This is a fairly straightforward type of layout, but I wanted to be very clear about the many-to-many nature of the user, org and roles.
I've been reading IAM and Cognito documentation, as well as how it relates to fine-grained control over DynamoDB items or S3 buckets - but many of the examples focus on a single user accessing their own data rather than a many-to-many role style layout.
How might one go about implementing this type of permission system on AWS?
(If policy definitions need to be updated with specific Identities (say, for an Organization), can that reliably be done in a programatic way - or is it ill-advised to modify policies on the fly like that?)
The above answer is outdated.
AWS has added Cognito-Groups recently. That provides more flexibility
You can use technique described in the article to achieve that:
https://aws.amazon.com/blogs/aws/new-amazon-cognito-groups-and-fine-grained-role-based-access-control-2/
Unfortunately the kind of permission system you are trying to implement is not possible with Cognito at the moment. With Cognito you can currently create unique identities for your users in an identity pool. Users can authenticate using any external provider such as Facebook, Amazon, Google, Twitter/Digits or any OpenId Connect Provider. Users can also authenticate through your own backend authentication process. After the user authenticates, Cognito creates a unique identity for that user. There’s a concept of an identity, but there’s no concept of groups. All users/identities within a one identity pool can get credentials from roles associated with that identity pool. Currently you can specify two roles: One role for authenticated identity and one role for unauthenticated identity. There’s no such feature at the moment where you can specify multiple groups for each identity and specify role on that group.
For more information on Cognito, you can refer to
https://aws.amazon.com/cognito/faqs/
http://docs.aws.amazon.com/cognito/devguide/getting-started/
Related
Help is required in the following problem we're facing 😔
Any tip would be much appreciated!
Details and environment:
A multi-tenant application that aims to provide a dedicated tenant per customer (organization), in order to achieve full separation.
AWS Cognito user pool as my users' datastore and authentication provider.
an "AWS Cognito user pool" per customer (org).
Role management - based on the built-in user pool groups. Group per role and the server-side verifies that a user's access token includes a group name in it's embedded group's list.
So far so good and everything is working as expected, using AWS Amplify's SDK, for the client side's implementation. Amplify performs well and allows me to do whatever I want. The server verifies group belonging etc.
The problem:
I want to restrict non-admin users (that doesn't belong to the "admin" group) from performing certain Cognito actions via Amplify.
2 Examples:
I want to disable non-admin users' ability to modify a specific attribute's value, via Amplify.
I want to disable non-admin users' ability to modify MFA settings for themselves, via Amplify.
The actual problem started when I wanted administrators to be able to set MFA (enable/disable) for other users, but in Cognito (as I understand it) only a user can set his own MFA settings.
What I saw and already tried:
Set read/write permissions for user attributes. So the specific attribute I want to protect is modifiable only via API calls with developer credentials. That way, admins can call my server to ask for attribute modification. The server verifies the role by a group belonging according to the access token and calls Cognito API. The problem with that solution is that it covers only the attribute modification scenario.
Create an AWS Cognito identity pool for each of the user pools. For every group in every user pool, create an AWS IAM role with a policy that would restrict or allow the wanted behavior. The could actually work. The problem with that solution is that it feels like a super-duper overkill, plus it requires me to create an extra identity pool and an IAM role for each user pool. It means that every new customer that joins the service, would require (1) user pool, (2) Cognito client application, (3) identity pool and (4) IAM Role (instead of just a user pool and Cognito client app). Essentially, implementing this solution.
The real question:
Can I restrict users in a certain group from performing actions on themselves, such as disabling the MFA (even that the user-pool's MFA is set to "Optional")?
Thank you all so much! any help would be appreciated!
Well... After long research, we have come to the understanding that there is no proper right way. Every possible solution has its own pros and cons. A consultant meeting with AWS's experts taught us that:
Options Overview:
[Server Side Only] - Solution #1 that I proposed is exactly as described. Drawbacks are the same. It could work, and access to user-attributes will be restricted. Any other action that another client would make will not be blocked.
[Identity Pools] - Solution #2 that I proposed is the most accurate one. Yet I described it with one big mistake: one identity-pool can serve multiple user-pools! So essentially, we could create only one IAM role and one identity-pool per app's role. Then we match every user-pool we want to that same identity-pool and when introducing a new role to the app - just create a new group in the user-pool and match it to the IAM role. This solution is not as complicated as thought, and it would definitely do the trick. As a bonus, you'll get the ability to control and allow access to different AWS services. That being said, it still requires management and effort.
[Post-Auth Lambda] - Solution #3 that was not mentioned here, and I started to work on a day after posting this post. I blocked the write permissions of a new boolean custom attribute called "MFA". It indicates the desired MFA configuration for the user. Only a server could edit its value (and users with the admin role will have access to the server's API endpoint that can modify it). We've deployed a lambda function that would be triggered after successful authentication (post auth trigger in Cognito user-pool). It would verify a match between the desired and current MFA configurations for the authenticated user. If there is a mismatch, throw the user out because he did something that is not allowed.
*To be exact, we created one more custom attribute called "mfa_status" and it is set to true after the user has set it's MFA configurations. The lambda checks if both MFA and mfa_status are true and the real current MFA Configurations are false. if this is the case - the user is thrown out.
The Chosen One:
The solution we picked eventually is #3 (Post-Auth lambda) as it is the most detached solution. It does not require any mix with our server or client's code, any special configurations that are specific to a user pool and it still allows us to keep working with the Cognito's Amplify SDK as a client.
Thank you all for your time, I hope this post would help someone in the future.
I have my enterprise Quicksight in place and with users using our company email to register an account (like john.doe#mycompany.com). We're using Gmail for business.
On the other hand we have developed another application backed by AWS Cognito user pool using Google as an identity provider, and since this is the same user base our intention was to use the same user pool for Quicksight access. In addition we will develop a Lambda that would synchronize Cognito user group association with Quicksight memberships if/when necessary.
I've followed the example described here https://aws.amazon.com/blogs/big-data/use-amazon-quicksight-federated-single-sign-on-with-amazon-cognito-user-pools/, but the problem is that even though I login as different users I get access to Quicksight via same IAM role. The Quicksight user associated with this role has a specific username starting with CognitoQuickSight1-AuthRole-KX4Y16... and email associated with the user I used to login the very first time.
Now I'm wondering if in this setup it's even possible to have different roles associated with different users so they can be differentiated on Quicksight side? Or is there any other way to achieve this?
I don't think you can assign QuickSight user specific permission on Federated users.
Some AWS services allows to use the user identity in the resource base IAM policy. For example S3 (to allow user to access only their 'directory' in a bucket) and DynamoBD (to allow user to only access item where their identity is the primary key).
According to https://docs.aws.amazon.com/quicksight/latest/user/security_iam_service-with-iam.html Quicksight does not support Resource based or Tag based policies.
I am new to AWS...
We have a home grown user authentication and authorization.
We define authorizations(roles) in company terms, role1 allows you to do tasks1 and tasks2. Role2 allows one to perform tasks3 only.
I can see how I can use Cognito for my user/password management.
Unclear if I use cognito for roles verification, i.e authorization.
Thoughts?
In a Cognito User Pool one can define both Users and Groups, which can be leveraged to drive fine-grained RBAC permissioning. You can define a custom attribute in the User model (e.g., "department" or "role") and map this attribute to Groups.
https://docs.aws.amazon.com/cognito/latest/developerguide/cognito-user-pools-user-groups.html
Each group can optionally be associated with an IAM role, so it's possible to restrict access to AWS resources (e.g., certain DynamoDB tables) by group -- as an additional layer of security.
However, if you don't need/want to map users to different IAM roles, maybe just handle authentication completely from within your application.
My production environment uses AWS cognito federated identities (AKA: identity pool) for allowing users to sign in with their Google/FB accounts. This is working fine.
However, for my staging environment I want to offer a similar sign in functionality (that is: users sign in in via Google) but I want to restrict the ability to sign in only to a specific whitelist (of, say, #gmail.com accounts). This is because the staging environment should only be accessed by team members and a bunch of trusted users.
My question is this: is it possible to define a Cognito identity pool that allows only the whitelisted users to sign in? if the answer is "yes", then how?
I know that I can do the whitelist checking at my backend (that is: at the backend of my staging env. I will reject every request not coming from these whitelisted users) but this is a bit unclean. In particular, I want the rejection to happen as early and possible and, ideally, to be carried out by cognito itself, and not by my backend.
Clarifications:
I mentioned a list of #gmail.com accounts as the whitelist. I am open to any other mechanism for defining the whitelist.
In a way I am asking whether I can have user directory functionality (in particular: determining if a user is in a certain group of users) with an cognito identity pool.
The purpose of the Identity pool is to provide access to authenticated identities. Therefore, this resource cannot manage users (ie: white listing a user group).
There are two ways to do this:
Link 3rd Party Identity into a User Pool and white list by User Group. Your user group will have a Roles and permission it will assume that will allow your test users to have the functionality they need without allowing other users who log to have that functionality.
Manage users from the 3rd Party Identity - I am not an expert at Google authentication.. but some OpenID providers allow you to create user groups with different access roles. This is an example for Google.
You can invoke a trigger and execute a lambda function when the user submits their information to accept or deny the sign in request.
I was reading up per subject matter and has a query on what is the best practice to handle user's authorization to AWS resources.
Scenario:
A 2-tiers windows application that access to AWS S3 and dynamoDB.
There are 2 groups of users - Admin and Normal User. Admin has read + write access, and Normal User has just the read access.
I'm trying to see if I could avoid a 3-tiers design. At such, I would like to access AWS resources directly from my application. In another word, I do not access AWS resources thru web services (that could do my user authorization check there).
Design:
I uses Web Identity Federation (google) to authenticate user and uses STS to get temporary credentials.
I've created 2 IAM Roles - AdminRole (with write+read policy) and UserRole (with read policy).
At this point, my thoughts are stuck on what is the best practice and securely choose which role to assume from my application.
Solution 1:
Create a UserRole table in dynamoDb with UserId and Role attributes.
After user has authenticated with google, I'll check the UserRole table against the userid returned from google to get the role of this user. Assuming I've pre-setup all the user's roles in the table.
I do not want to hardcode or expose my AWS secret key onto my app, but for the above execution, I've created a secret key with a role and policy only to the [UserRole] table.
At this point, I would know which role to assume from my app when I get the temporary credential using STS.
However, with the above solution, I see that there is one security loophole. If someone is able to get hold of my application id used for my IAM role, and with some brute-force effort on my IAM roles' name, that person can easily gain temporary credential with AdminRole.
(added) Solution 2:
I create just 1 IAM role - GoogleUserRole
In the policy portion, I allow write access to admin user by using their Federated userid.
I'm still new with writing AWS policies, but I think I've read somewhere that I could have this fine-grained control to the specified user(s). This could be feasible if my users based are small, but not very feasible when my user base grows.
Welcome any thoughts and advises.
Thanks.