AWS IAM Role permission issue

Question

We have just built a new Things Enterprise server hosted at AWS on an EC2 instance and created an application to use AWS IOT. We are getting the following error

“message”: “User: arn:aws:sts::446971925991:assumed-role/Things-Enterprise-Stack-Srv-StackIAMRole-DBHBSMSY05AQ/i-095895d605fab3fa4 is not authorized to perform: sts:AssumeRole on resource: arn:aws:iam::446971925991:role/Bosh-Parking-IOT-Stack-TheThingsStackRoleCD9FBAD2-C44RRJJ53M93”

I have been told

What is the execution role of the TTES instance that is trying to assume the role? The role TTES needs to be able to assume that role. That will give the right permissions.

But I'm not sure what that means, i'm presuming i need to add / alter some permissions within an IAM role. Can someone point me in the right direction Pls.

Marcin Marcin · Accepted Answer · 2020-09-16T08:22:09

From the error message it seems that your IAM role for Amazon EC2 has no permissions to assume a role Bosh-Parking-IOT-Stack-TheThingsStackRoleCD9FBAD2-C44RRJJ53M93.

To add such permissions manually you can do the following:

Go to IAM Console->Roles.
In the Roles window, you can use Search bar to locate Things-Enterprise-Stack-Srv-StackIAMRole-DBHBSMSY05AQ role.
Once you find the role, you click on Add inline policy.
Once Create policy window shows, you can go to JSON tab and add the following JSON policy:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "AllowAssumeRole",
            "Effect": "Allow",
            "Action": "sts:AssumeRole",
            "Resource": "arn:aws:iam::446971925991:role/Bosh-Parking-IOT-Stack-TheThingsStackRoleCD9FBAD2-C44RRJJ53M93"
        }
    ]
}

Then click Review Policy, name the policy (e.g. PolicyToAssumeRole) and Create policy

However, based on your policy names (e.g. Stack-Srv-StackIAMRole) it is possible that they have been create by CloudFormation. If this is the case, then manually changing the roles as described above is a bad practice and will lead to drift. Any changes to resources created by CloudFormation should be done using CloudFormation. Sadly, your question does not provide any details about CloudFormation templates used, therefore its difficult to comment on that more.

AWS IAM Role permission issue

1 Answers