A Beginner’s Guide to AWS IAM (Identity and Access Management)

AWS Identity and Access Management (IAM) is a web service that helps you securely control access to AWS services and resources for your users. With IAM, you can create and manage AWS users and groups, and use permissions to allow and deny their access to AWS resources.

Key Concepts

1. Users

• Definition: An individual user in AWS is an entity that you create in IAM to represent the person or application that interacts with AWS.
• Example: Jane, a developer in your team, needs access to certain AWS services. You create an IAM user named “Jane”.

2. Groups

• Definition: A group is a collection of IAM users. You can use groups to specify permissions for multiple users, which can make it easier to manage the permissions for those users.
• Example: You have several developers who need similar access. You create a group called “Developers” and add all developer users to this group.

3. Roles

• Definition: A role is an IAM identity that you can create in your account that has specific permissions. It is intended to be assumable by anyone who needs it.
• Example: An application running on an EC2 instance needs to access AWS services. You create a role with the necessary permissions and assign it to the EC2 instance.

4. Policies

• Definition: Policies are documents that define permissions. They are written in JSON and specify what actions are allowed or denied for specific resources.
• Example: You create a policy that allows access to S3 buckets and attach it to the “Developers” group.

Creating an IAM User

Step-by-Step Guide:

1. Sign in to the AWS Management Console: Open the IAM console at https://console.aws.amazon.com/iam/.
2. In the navigation pane, choose “Users”.
3. Choose “Add user”.
4. Enter the user details: Provide a username (e.g., “Jane”).
5. Select the type of access: Choose whether the user will have “Programmatic access” (via API, CLI, SDK) and/or “AWS Management Console access”.
6. Set permissions: You can add the user to a group, copy permissions from an existing user, attach policies directly, or set permissions boundaries.
7. Review and create: Review the user details and choose “Create user”.

Creating and Managing Groups

Step-by-Step Guide:

1. Sign in to the AWS Management Console: Open the IAM console at https://console.aws.amazon.com/iam/.
2. In the navigation pane, choose “Groups”.
3. Choose “Create New Group”.
4. Enter the group name: Provide a name for your group (e.g., “Developers”).
5. Attach policies: Choose policies to attach to the group. For example, you might attach the “AmazonS3ReadOnlyAccess” policy.
6. Create group: Review and choose “Create group”.

Creating a Role

Step-by-Step Guide:

1. Sign in to the AWS Management Console: Open the IAM console at https://console.aws.amazon.com/iam/.
2. In the navigation pane, choose “Roles”.
3. Choose “Create role”.
4. Select trusted entity: Choose the AWS service that will use this role (e.g., EC2).
5. Attach permissions policies: Select policies to attach to the role. For example, you might attach the “AmazonS3FullAccess” policy.
6. Set role name and description: Provide a name and optionally a description for the role.
7. Create role: Review and choose “Create role”.

Attaching Policies

Step-by-Step Guide:

1. Sign in to the AWS Management Console: Open the IAM console at https://console.aws.amazon.com/iam/.
2. In the navigation pane, choose “Policies”.
3. Choose “Create policy”.
4. Create a policy: You can write the policy in JSON or use the visual editor to specify actions and resources.
5. Review policy: Review the policy JSON, give it a name, and choose “Create policy”.

Best Practices

1. Use Groups to Assign Permissions: Instead of assigning permissions to individual users, assign them to groups.
2. Grant Least Privilege: Give users only the permissions they need to perform their job.
3. Enable MFA (Multi-Factor Authentication): Increase security for your AWS account by enabling MFA.
4. Rotate Credentials Regularly: Change your passwords and access keys regularly to maintain security.
5. Use Roles for Applications: Use IAM roles instead of storing credentials within applications.

Conclusion

AWS IAM is a powerful tool that helps you manage access to your AWS resources securely. By understanding and utilizing users, groups, roles, and policies, you can efficiently manage permissions and ensure your AWS environment remains secure.

Example Scenario:

Let’s say you have a team of developers who need read-only access to S3 and full access to DynamoDB. You can achieve this as follows:

1. Create an IAM group named “Developers”.
2. Attach the “AmazonS3ReadOnlyAccess” and “AmazonDynamoDBFullAccess” policies to the “Developers” group.
3. Add each developer as an IAM user.
4. Add each user to the “Developers” group.

By following these steps, you ensure that your developers have the necessary permissions while maintaining a structured and secure IAM setup.