AWS Security: Delegation & Cross-Account Access

1. Introduction

In AWS, security is paramount. One of the essential components of AWS security is managing access to resources. This lesson covers the concepts of delegation and cross-account access, allowing organizations to securely manage resources across multiple AWS accounts.

2. Key Concepts

• Delegation: The process of granting permissions to allow other IAM users or roles to perform actions on your behalf.
• Cross-Account Access: Enabling IAM roles or users in one AWS account to access resources in another AWS account.
• IAM Roles: A set of permissions that define what actions are allowed and under what conditions.
• Trust Policy: A document that defines who can assume a role.

3. Delegation

Delegation in AWS IAM allows you to grant permissions to other users or services. Here’s how to set up delegation:

Step-by-Step Process:

1. Navigate to the IAM Console in AWS Management Console.
2. Select the user or role you want to delegate permissions to.
3. Go to the "Permissions" tab and click "Add permissions".
4. Choose "Attach existing policies directly" or "Create policy" to define specific permissions.
5. Review and save changes.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "s3:ListBucket",
            "Resource": "arn:aws:s3:::example-bucket"
        }
    ]
}

4. Cross-Account Access

To enable cross-account access, follow these steps:

Step-by-Step Process:

1. Log in to the target AWS account where you want to grant access.
2. Create an IAM role that specifies the permissions you want to grant.
3. Define a trust policy that specifies which AWS account (the source account) can assume the role.
4. In the source account, create an IAM user and grant it permissions to assume the role from the target account.
5. Use the AWS CLI or SDK to assume the role and access resources in the target account.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Principal": {
                "AWS": "arn:aws:iam::123456789012:root"
            },
            "Action": "sts:AssumeRole"
        }
    ]
}

5. Best Practices

• Use IAM roles instead of users for automated services and applications.
• Grant least privilege access—only assign permissions that are necessary.
• Regularly review permissions and access logs.
• Use MFA (Multi-Factor Authentication) for sensitive operations.

6. FAQ

7. Flowchart

graph TD;
    A[Start] --> B{Is access needed?}
    B -- Yes --> C[Identify the account]
    C --> D[Create IAM role]
    D --> E[Define trust policy]
    E --> F[User grants access]
    F --> G[Access granted]
    B -- No --> H[End]