IAM_Troubleshooting

Granting Permissions for AWSLabsUser to Attach Policies to Roles

In this guide, we'll go over various options to allow the AWSLabsUser in AWS to attach policies to roles, including both predefined and custom policies.

Issue Overview

When trying to attach a policy to a role, the action iam:AttachRolePolicy fails because there is no existing identity-based policy allowing this action for AWSLabsUser. This guide provides different options for granting this permission.

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Option 1: Attach the IAMFullAccess Policy

Description

The IAMFullAccess managed policy grants full permissions over IAM resources, including the ability to manage users, roles, policies, and groups.

Usage

1. Go to the IAM console.
2. Attach the IAMFullAccess policy to the AWSLabsUser user.

Policy Example

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "iam:*",
      "Resource": "*"
    }
  ]
} 

Option 2: Attach the PowerUserAccess Policy with Additional Custom Permissions

Description

The PowerUserAccess policy provides broad administrative access except for IAM management. You can attach this policy along with a custom policy to allow only specific IAM actions, such as attaching policies to roles.

Usage

1. Attach PowerUserAccess to the AWSLabsUser.
2. Create a custom policy allowing iam:AttachRolePolicy for specific roles.

Custom Policy Example

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "iam:AttachRolePolicy",
      "Resource": "arn:aws:iam::<AccountID>:role/TargetRoleName"
    }
  ]
} 

Option 3: Allow Role Switching with Cross-Account Access

If you need AWSLabsUser to attach policies across accounts, you can use a combination of permissions and trust policies.

Steps

1. In the Source Account: Attach a policy to AWSLabsUser allowing sts:AssumeRole on the target account role.
2. In the Target Account: Modify the role’s trust policy to allow AWSLabsUser to assume it.

Source Account Policy Example

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "sts:AssumeRole",
      "Resource": "arn:aws:iam::<TargetAccountID>:role/TargetRoleName"
    }
  ]
}