AWS limited multi tenant IAM roles - amazon-web-services

I'm planning to develop a multi tenant platform based on the AWS stack. For each customer, let's call them customerA and customerB I want to create individual resources and restrict them that customerA can't see all stuff from customerB.
The first step to set up for the customer is to set up an IAM user with rights to manage all rights for the user. So I want to give the IAM user the rights to create IAM roles and policies and assign them to users but only for the ARN with the resource name customerA__* as prefix. This way it's possible to give the user the rights to create for example roles giving dynamoDB create table rights with a role name of customerA__rolename as planned but I want to further limit it that all roles also need to be bound to this scope, otherwise customerA__deleteTable could also be used to delete customerBs tables.
So in short: Is it possible to create an IAM role that limits all rights to have the name customerA__xyz and also to limit it's scope for each created role to resources with the name customerA__*
If it's not possible any other suggestions how to set up multi tenant rights for AWS? I don't want to create a separate AWS account for each customer for separation and I doubt this can be automated in a legal way.
Thanks in advance :)

There is indeed functionality for this by writing a permission boundary that prevents an IAM user from actually granting more permissions than they already have (which would allow them to bypass this).
A permissions boundary will be evaluated before the permissions so it will take a higher precedence than any permissions a user can set.
AWS have actually created a thorough policy you can use for this use case on their How can I use permissions boundaries to limit the scope of IAM users and roles and prevent privilege escalation? documentation page.
If you add this within your account you should be able to validate that it provides the functionality that you're expecting.

Related

What AWS IAM Policy to grant Admin right only on ressources created by your Identity?

I have an AWS account used by different people.
I want to give access to IAM Users in the IAM User Group Developer to only the resources they created. They should be able to create any resources and read and write all the resources they created.
So, when you logged as IAM User A part of IAM User Group Developer, you can read and edit all the resources IAM User A has created since the beginning. Also, you will be able to create any other resources.
I prefer to avoid using AWS Organisations. Moreover, there are resources shared across the account. There is already an Admin role and a ReadOnly role for these resources.
One solution would be to ask developers to use their AWS Accounts and permit them to access the main one with IAM Roles. However, I would like your help with a solution using only one AWS Account.

How to Map Users with Groups (IAM) with Organisation Unit?

Related to AWS:
I've been trying to search for an answer about the Users and Groups that I have created using IAM (AWS), how can I map those Groups with the Organization Unit(s)?
For example: I have a Group called 'Developers' where Users (say 5 Users) are member of it.
Now, I have an Organization Unit of 'ApplicationsDevelopment&Services' where I need to give access to 'Developers'. Can I associate Groups with OUs, so that members of that Group get necessary access.
I have some policies (SCP) applied on that OU, to manage the access boundaries of Developers.
Please suggest if there is a way to do it or something else needs to be done like ActiveDirectory setup (whole new setup)?
Thank You,
Varun Gupta
I recommend to have a look into AWS SSO (https://aws.amazon.com/single-sign-on/?nc1=h_ls). It comes with no additional cost, is enabled with one click and lets you easily assign cross-account role access to Groups/Users.
Going with an IAM Group which you like to have access to all accounts inside one OU, create roles inside those accounts with a trust relationship to the user/group account. You can use a CloudFormation StackSet to enroll the Stack on OU level. Allow sts:AssumeRole for the particular group, resource section pointing to the role you deployed through the StackSet (leave the account_id blank).
Then everyone inside the group should be able to assume the role and deployment of the cross-account role is centralized.
AWS Org SCPs have account or OU scope, they are not for individual IAM users or roles. From aws blog:
Central security administrators use service control policies (SCPs) with AWS Organizations to establish controls that all IAM principals (users and roles) adhere to.
At the account level, a similar type of maximum permissions gourds on individual users or roles (not groups) can be set using permission boundries. Thus, if you have any roles mapped to your uses through AD, you can look at attaching permissions boundaries to them. But, note that permissions boundaries are an advanced IAM topic, thus its not clear for me how exactly they would apply to your use-case.

Is there a way to add a description for IAM users in AWS?

I have users that have been added by other admins in my AWS account. I am afraid that these users might get deleted by other people.
Is there a way to add a description to an IAM user?
I don't see any way to add description/tag when you create an IAM user. One suggestion is to create a IAM group for each admin and add the user to the admin's group when a user is created/added. You can have group(s) with no policy attached.
There is currently no way to add a description to a user. There are a number of better ways to solve your core issue however. Some of the IAM Best Practices specific to your use case include:
Use AWS Defined Policies to Assign Permissions Whenever Possible - AWS-managed policies are designed to support common tasks, such as deleting and creating users. Assign these policies to the users that need them.
Grant Least Privilege - Granting only the permissions required to perform a task. Determine what users need to do and then craft policies for them that let the users perform only those tasks. This is probably the most important factor in preventing users from being deleted accidentally.
Monitor Activity in Your AWS Account - You can use logging features in AWS to determine the actions users have taken in your account, including deletion of users either accidentally or on purpose. Two very useful tools you should be using in this regard include:
AWS CloudTrail - CloudTrail provides event history of your AWS account activity, including actions taken through the AWS Management Console, including user deletions.
AWS Config – Provides detailed historical information about the configuration of your AWS resources, including your IAM users, groups, roles, and policies.
As you can see, utilising the built-in tools that AWS provides can assist you in preventing administrators from deleting users unnecessarily.
As a workaround, you can add a TAG to your user with its key named "DESCRIPTION" and put in the description as a value. Note that for the value, you are very limited to the characters you can use. For instance, you cannot use the apostrophe ('). But it is better than nothing.

What policy do I need to add to a IAM group to allow access to Amazon Product API

While trying to follow the advice given when first accessing the IAM console I created a new user and a group to hold that user.
But I've not been able to find a suitable Policy to add to the group to allow the user access to the Amazon Product API.
Can anybody point me at the right Policy so I don't have to use my Root Key/Token.
IAM roles are not currently supported. You must use the root account credentials.
http://docs.aws.amazon.com/AWSECommerceService/latest/GSG/GettingStarted.html
This is an admittedly odd use of the phrase "IAM roles," since an IAM role means something different, in proper IAM terminology than the usage, here, suggests... but "you must use the root account credentials" seems to confirm that IAM users aren't supported, either... so there is no policy you can create that will enable an IAM user to access this particular service.
It seems as if perhaps the term IAM roles has been casually substituted in the documentation in place of the (perhaps) more accurate term IAM identities.

AWS IAM Role vs Group

The AWS official site reads role as a collection of permissions and group as a collection of users. But still they look the same to me. You attach policies to groups or roles, and then assign groups or roles to a user. What exactly are the differences between role and group?
Short answer for googlers: you can't assign role to user.
group is a bunch of users with the same policies
role is a preset of policies for service(s)
Users can asume roles according to AWS docs:
Assuming a Role
AWS Groups are the standard groups which you can consider as collection of several users and a user can belong to multiple groups.
AWS IAM Roles are all together different species; they operate like individual users except that they work mostly towards the impersonation style and perform communication with AWS API calls without specifying the credentials.
Given that IAM Roles are little different, I am emphasizing only that. There are several types of IAM Roles like EC2 IAM Roles, Lambda etc. If you consider, you can launch an EC2 instance with an EC2 IAM Role; hence forth any AWS API related communication wouldn't require any AWS Access Key or Secret key for authentication rather can call the APIs directly (however the long answer is - it uses STS and continuously recycles the credentials behind the scenes); the privileges or permissions of what it can do is determined by the IAM Policies attached to the IAM Role.
Lambda IAM Role works exactly the same, except that only Lambda function can use the Lambda IAM Role etc.
Users: End User (Think People).
Groups: A collection of users under one set of permissions (permission as policy). As per IAM standards we create groups with permissions and then assign user to that group.
Role: you create roles and assign them to AWS resource (AWS resource example can be a customer, supplier, contractor, employee, an EC2 instance, some external application outside AWS) but remember you can't assign role to user.
It’s not only users who will login, sometimes applications need access to AWS resources. For example, an EC2 instance might need to access one or more S3 buckets. Then, an IAM role needs to be created and attached to the EC2 instance. That role can be re-used by different EC2 instances.
Remember : Groups are for living. Roles are for non-living.
I think of an AWS Role as a kind of 'sudo', where each AWS Role can temporarily provide a very specific set of elevated privileges, but without needing the elevated credentials. I get the impression that like sudo, AWS Roles try to prevent privileged actions being used accidentally.
I'd be interested to hear if others agree with this analogy.
Please note that Groups are specific to local IAM users, which are not federated, and local IAM user logs do not show who has done the actions (i.e.., multiple people or applications could use the same long-term secret/access keys, and there is no record of which entity used them). If you must use local IAM users, you can place them into IAM Groups. Where this can be especially useful is to serve as a boundary -- you could place a deny policy on the group, restricting access to specific services or actions, and that deny policy will be applied to all users in the Group.
Conversely, roles can be federated, whereas local IAM users are not. You might create an on-premises AD group that serves as a member container, for example, and then the members of that AD group (and only they) can use the role that the AD group correlates to, with whatever allow or deny policies and/or permissions boundaries you've applied to the role. (Here is a link explaining the AWS ADFS federation.)
Importantly, roles allow for temporary session credentials (which is a best security practice), as their session tokens expire after a maximum of 12 hours. Equally importantly, roles do show in the logs which of the AD members with access to use the role actually did the action. You'll find this tacked to the end of the role ARN in the logs (e.g., a user ID). CloudTrail would be one of several services that indicate user activity. This is important from a logging standpoint.
Understanding IAM roles vs IAM groups (IAM indentities) is very important foundational concept . Its important to look at difference between IAM role and IAM user as essentially group is just a bunch of users performing similar functions (eg. group of developers, QA's etc.) Roles are not uniquely associated with one person (user), they can be assumed by user,resource or service who needs it to perform task at that point of time (session). Roles do not provide long-term credentials like password or access keys.
Best practice recommendation is to require workloads to use temporary credentials with IAM roles to access AWS
Please refer to link below for more clarity:
https://docs.aws.amazon.com/IAM/latest/UserGuide/id.html
I was confused all the time about the difference between these two functions.
In short,
Role is like a tag with all the preset policies that can attach on IAM users/groups or AWS services. IAM users share the same account with the account root user (Admin) but with assigned permissions by the root user to use AWS resources within that account.
Therefore, IAM users can directly interact with AWS services; whereas IAM roles cannot make direct requests to AWS services, they are meant to be assumed by authorised entities like an IAM user or an instance. https://aws.amazon.com/iam/faqs/
I had a hard time deciphering the spirit of the given answers..
Here's what I've found:
Groups:
Intended to represent human users created within IAM who need identical policies.
Ex. Dev 1 - Dev 8 are all developers, and all need access to create dev servers.
This is similar to traditional desktop users/groups, but for HUMAN users only.
Roles:
Roles rotate automatic credentials, meaning password input isn't needed for accessing policies.
This makes it good for two things:
Giving permissions to non-humans, such as services / applications.
Ex. EC2 of type A needs access to S3 of type B.
Giving permissions to federated / outside users & groups.
Ex. Contractor A # Outside Company A needs access to your Server A.
Authentication of users & groups are handled by some service, like Azure AD.
Authorizations are then mapped to your IAM role(s), NOT users or groups.
Note: I've used Jumpcloud's Article & AWS's Documentation to gather this information. The terms "Group", "Role", and "User" become overloaded in context to SSO+IdP, and IAM.
Here's an image showing how they map roles. !Need 10 Reputation :(
Aside: There is a way of assigning Roles to normal IAM Users & Groups, but it appears to be bad practice.
Hopefully this provides clarity to the answers above.
Only one IAM Role can be assumed at a time! And there are several
situations which fits exactly this kind of permission.
Read the faq about: How many IAM roles can I assume?
The underlaying tool in use is "Permission" in both of the use cases namely: Group and IAM Role.
Group or IAM Role --> Has Policy --> Policy defines permisions --> Permissions are assigned to a Group or IAM Role.