I want to be able to specify an iam group as the principal within my policy but i have been reading that you cannot specify an iam group as part of a resource based policy. I could potentially add in a list of iam users but then my policy would look really messy. What is the best approach to take if i cannot add an iam group arn as the principal within my policy.
If you cannot specify an IAM group as the principal in a resource-based policy, you have a few options:
Attach the policy directly to the IAM users: In this case, you would
need to specify each IAM user ARN in the policy. This approach can
quickly become messy and difficult to manage as the number of IAM
users grows.
Use an IAM role: An IAM role is a way to grant permissions to AWS
services or applications that run on AWS. You can create an IAM role
that can be assumed by IAM users or IAM groups. You can then specify
the IAM role in the policy instead of the IAM users or IAM groups.
This approach provides a cleaner and more scalable way to manage
permissions.
Use a service control policy (SCP): An SCP is a type of policy that
is used to set permissions boundaries for an AWS account. You can
use an SCP to allow or deny access to AWS services for IAM groups,
IAM users, or IAM roles. This allows you to manage permissions for
multiple users in a centralized and organized manner.
I would recommend option 2 or 3 as the best approach, as they provide a cleaner and more scalable way to manage permissions compared to specifying individual IAM user ARNs in the policy.
Related
I am using metricbeat to monitor metrics from a few AWS accounts. I have read through the doc: https://www.elastic.co/guide/en/beats/metricbeat/current/metricbeat-module-aws.html
it says to configure the credential as environment variables or in aws credential file. But I'd like to use cross account IAM policy to access different AWS account. That means metricbeat needs to assume a role when it tries to query metrics. How can I achieve this in metrcibeat? I can't find related doc in their document.
So you can specify the IAM Role like this
Metricbeat Configuration Params
metricbeat.modules:
- module: aws
period: 300s
metricsets:
- ec2
role_arn: arn:aws:iam::123456789012:role/test-mb
I would say there is nothing like Cross Account Policy.
Your role has permissions based on the policies you assign to it via IAM Policies.
When you wanna use Cross-Account IAM Roles, you still have to assign IAM Policies on the role you create in the destination account + an IAM Trust Policy as well so that you can assume the role from another account, In addition to that your source IAM Role must have permissions to assume the destination IAM Role
IAM Role Delegation
How to use trust policies with IAM roles
IAM Tutorial: Delegate access across AWS accounts using IAM roles
Am I able to allow a newly created IAM user to create arbitrary policies but limited to resources he created? For example if I allow a user to create S3 buckets, users and IAM/Bucket policies, I want him to be able to create policies for IAM user that are limited to buckets he created and not other buckets present in the account.
If I'm not able to specify such policy, is there any other way to achieve this? Some kind of namespacing within an account that could isolate that user's resources from all other IAM users?
This is related to AWS IAM Policy to allow user to create IAM User with specific Policy/Roles and I was wondering if something has changed since the time it was asked.
Check out Delegate permission management to developers by using IAM permissions boundaries
The documentation Permissions boundaries for IAM entities
AWS supports permissions boundaries for IAM entities (users or roles). A permissions boundary is an advanced feature for using a managed policy to set the maximum permissions that an identity-based policy can grant to an IAM entity. An entity's permissions boundary allows it to perform only the actions that are allowed by both its identity-based policies and its permissions boundaries
If a user in AWS is having AdministratorAccess policy attached, he has full AWS access for that account. But with permission boundaries attached to that user his access can be confined. For example say the user has permission boundaries set to AmazonDynamoDBFullAccess, then the full access is just confined to DynamoDB.
What is real benefit of above approach, one could have just removed the AdministratorAccess policy and attached AmazonDynamoDBFullAccess to the user to achieve the same restrictions/permissions.
Is there anything more to understand?
That is not not purpose of IAM Permission Boundaries, nor is it the way it operates.
From Permissions boundaries for IAM entities - AWS Identity and Access Management:
AWS supports permissions boundaries for IAM entities (users or roles). A permissions boundary is an advanced feature for using a managed policy to set the maximum permissions that an identity-based policy can grant to an IAM entity. An entity's permissions boundary allows it to perform only the actions that are allowed by both its identity-based policies and its permissions boundaries.
To explain via an example, let's say that a developer needs permission to create an IAM Role in their software development duties. This can be a very dangerous permission to assign because they could create a Role that has full Admin permissions, thereby granting themselves even more permission that desired.
To limit their abilities, a permission boundary could be added to the developer such that they are only able to create an IAM Role if the role they define is attached to a permission boundary that limits the permissions of the Role (eg so it can only be used to access S3 and DynamoDB, but not other services). It can be a little confusing, but think of it as a set of rules that must be attached to any permissions they give, so that they can't grant full permissions. It's a way to grant them permissions, but limits what permissions they can on-grant to other entities.
This concept is totally separate to assigning IAM managed policies that you mention in your question. In most circumstances, assigning an IAM managed policy is perfectly sufficient. Permissions boundaries only really apply when somebody has permission to create new IAM entities.
Suppose, I am AWS IAM user, is there any way so that I can check what resource permission has been given to me, using CLI or Console.
Unfortunately, there is no comprehensive tool for that. In IAM console you can only check your user's IAM profile or group permission you belong to.
But full set of privileges is a very complex thing to get. Apart from obvious IAM user or group permissions you can have:
IAM roles which you can assume,
resource policies which you are listed as a principle (e.g. bucket policy, kms key policy),
resource policies where a role you can assume is a principle,
cross-account permissions in IAM roles or resource policies,
AWS Organization level SCP permissions.
If the reason for asking this question is related to security, e.g., to check what resources were accessed by a compromised IAM user credentials, you suspend the credentials or delete the user. Also can inspect the CloudTrial history to check what resources a given IAM user accessed.
I am learning AWS IAM and I understand that an IAM role is meant for a specific AWS resource to access other resources , while IAM groups are a group of users that can be attached to a policy.
I want to understand the scenarios in which the users may be given an IAM role instead of an IAM group, because from what I understand both have managed policies that can restrict users.