I have two AWS account (A and B). On my account A, I have a lambda function which need to access to resources of account B.
Precisely, my lambda on my account A, need to update a record in a Route53 zone hosted on my account B.
Contrary to S3, I don't see any resource access policy in Route53. So I'm a bit lost.
I tried to play with IAM cross account roles, but that does not seems to work with lambda.
How can I allow a lambda function on an account A to access resources of my account B?
You can create a Role in account B and permit your User (in account A) to assume it.
Create a Role in account A that will be used by your AWS Lambda function.
Create a Role in account B with a role type of Role for Cross-Account Access. Assign the desired permissions to use Route 53 in account B. Also add permissions for the Role in account A to call AssumeRole on this role.
The Lambda function in account A can then call AssumeRole on the role in account B. This will return a set of temporary credentials that can be used to access Route 53 in account B.
See:
Tutorial: Delegate Access Across AWS Accounts Using IAM Roles
Creating a Role to Delegate Permissions to an IAM User
Here's a picture from the Tutorial:
Related
Was trying to start a session[terminal] via ssm on an instance in another account. using command
aws ssm start-session --target i-yyyaf4692d801d1xx --region ap-south-1
but it was failing with response as "Target is not connected".
we get this response when the instance is usually not found in the inventory of Systems Manager. - which i can't add, as the instance is in another account
END Goal: I wish to use users created in Account A to be able to start sessions on instances on Account B. both part of the same organisation.
Also,
my user has appropriate permissions have verified it through IAM Simulator
it seems instance IDs are unique and associated to one account only.
the instance is accessible by local users in that account.
[update 9th Jan 2023]
Thanks for the responses, its clear that IAM Role[with assume role sts] suffices the request conditions.
But i was looking for some seamless method, where we dont need to generate temporary credentials and use them for access each time.
May be a script to do this task or something would do. As IAM Principal: Users need to generate temp creds manually which is not the case with IAM Roles
You need to delegate access between the accounts. You can do this by creating a role in the target account which is allowed to assumed by users in the other account.
Setup the access:
Create an IAM role with necessary IAM permissions to access the instances in the target account (account B)
Create a trust relationship on the role in the target account to trust the appropriate principals (users or roles) in the source account (account A).
Grant the appropriate principals (users or roles) in the the source account (account A) permission to call the sts assume-role API for the role in the target account (account B)
Use the access:
From your user profile or role in account A, call the sts assume-role API to obtain credentials for the role you created in account B.
Use the credentials returned by the sts assume-role call in order to call the API using the identity assumed in account B to access the resources.
See: cross-account IAM access for more details.
There is an AWS account A, which has a resource X managed by policy Pax. It adds the second AWS account B to a role which attaches the policy Pax, let's call this role Rax. Now within the AWS account B, I create another policy for assuming role Rax, let's call it Pbrax and added it to a role RPbrax where the Principal is an AWS account C.
When I try to access the resource X via the account C, I get access denied. I cannot touch anything in AWS account A, but in B and C.
Role permissions are not cumulative.
This means the history of the role chaining doesn't help you - the principal in account C needs to have its own access to the resources in account X if needs to access them.
Say I set up a AWS organization from account 111111111111, and then I create/invite 2 accounts, 222222222222 and 33333333333. As soon as I enabled SCP, I see a FullAWSAccess Policy attached to all members. I am trying to update each account programmatically in AWS SDK, and not having to switch roles on Console each time. For example:
AWSOrganizations client = AWSOrganizationsClientBuilder.standard().build();
ListAccountsResult result = client.listAccounts(new ListAccountsRequest().withMaxResults(10))
result.getAccounts()
.stream()
.forEach(account -> {
// I am not sure what to do with below data
// account.getArn()
// account.getId()
})
Say I want each member to put a s3 object like so:
s3.putObject(..)
Do I need to assume a role (AWS creates a OrganizationAccountAccessRole role by default) for each member account and call AWS service? Or am I missing something?
Your assumption is correct, in order to execute actions in other member accounts you need to assume a role in that account first. AWS Organizations creates OrganizationAccountAccessRole in each newly created account, this role has a trust policy to trust the master account. So as long as you're authenticated to the master account with any role that has sts:AssumeRole action you can assume OrganizationAccountAccessRole in the target account and do the "needfuls".
As the best practise you should your own automation role in each account and a dedicated automation account. This automation role lets say "pipeline-role" will have limited permissions that can be assumed only from your automation account.
This way you're reducing the need to utilise your master account and also making this automation role only as powerful as your automation needs instead of using the full AdministratorAccess policy.
I have a cloudfront, let's say in Account A and I want to access this cloudfront from a build server which is in another AWS account let's say in Account B with IAM Role.
How to give a IAM role access(Account B) to that cloudfront which is in Account A.
Note: Please consider Role not IAM user.
Overview of Managing Access Permissions to Your CloudFront Resources
An AWS account owns the resources that are created in the account,
regardless of who created the resources. Specifically, the resource
owner is the AWS account of the principal entity (that is, the root
account, an IAM user, or an IAM role) that authenticates the resource
creation request.
The following examples illustrate how this works:
Attach a permissions policy to a role (grant cross-account
permissions) – You can grant permissions to perform CloudFront actions
to a user that was created in another AWS account. To do so, you
attach a permissions policy to an IAM role, and then you allow the
user in the other account to assume the role. The following example
explains how this works for two AWS accounts, account A and account B:
Account A administrator creates an IAM role and attaches to the role a
permissions policy that grants permissions to create or access
resources that are owned by account A.
Account A administrator attaches a trust policy to the role. The trust
policy identifies account B as the principal that can assume the role.
Account B administrator can then delegate permissions to assume the
role to users or groups in account B. This allows users in account B
to create or access resources in account A.
For more information about how to delegate permissions to users in
another AWS account, see Access Management in the IAM User Guide.
I am looking to use AWS STS to access resources from another AWS account owned by another team.
say, AWS Account A trying to access AWS Account B.
basically the steps I am following:
1. Create a user in Account A
2. Create Role in Account B with the necesaary permissions
3. Add assume role permissions for user in Account A
4. Use User credentials to get temporary credentials for Account B.
5. Use temp credentials on Account B.
But, after reading through a ton of AWS docs, I am unable to figure out which account gets billed for the cross account API calls?
When you use AssumeRole to grant access to another Amazon account (account B), your identity switches to the other account with the username being the role name that you assumed.
The only cross account API being called will be AssumeRole. After this succeeds you will be using the APIs using account B's temporary credentials that were returned from AssumeRole.
All ownership, billing, etc. will be the same as if you had originally logged into account B as a normal IAM user except for the user name.
CloudTrail records STS type calls such as AssumeRole and logs all authenticated API requests. Once AssumeRole succeeds, your activity (using the temporary credentials) will be logged by CloudTrail in account B. This assumes of course that CloudTrail is enabled.
This link will give you more details into the user identity that AWS uses when using AssumeRole.
CloudTrail userIdentity Element
When you create a role for cross-account access, you establish trust from the account that owns the role and the resources (trusting account) to the account that contains the users (trusted account). To do this, you specify the trusted account number as the Principal in the role's trust policy. That allows potentially any user in the trusted account to assume the role. To complete the configuration, the administrator of the trusted account must give specific groups or users in that account permission to switch to the role.
Link
As everyone has mentioned a user from the account A is just assuming a role in account B to temporary access resources in account B,ownership stays still and the owner pays for the resources he owns. In this case it is the account B who pays. STS is the service being used to assume a role and is part of IAM.
The following was taken from IAM FAQ.
Q: How do I assume an IAM role?
You assume an IAM role by calling the AWS Security Token Service (STS) AssumeRole APIs (in other words, AssumeRole, AssumeRoleWithWebIdentity, and AssumeRoleWithSAML). These APIs return a set of temporary security credentials that applications can then use to sign requests to AWS service APIs.
Q: How many IAM roles can I assume?
There is no limit to the number of IAM roles you can assume, but you can only act as one IAM role when making requests to AWS services.
Q: Who can use IAM roles?
Any AWS customer can use IAM roles.
Q: How much do IAM roles cost?
IAM roles are free of charge. You will continue to pay for any resources a role in your AWS account consumes.