Role-based access control (RBAC)

Role-based access control (RBAC) is a key concept in ensuring that users within an organization only have access to the resources they need to perform their job functions. This security approach restricts access to information and commands based on the roles of individual users within an organization.

In the context of AWS and for individuals preparing for the AWS Certified Developer – Associate (DVA-C02) exam, understanding how RBAC is implemented in AWS using AWS Identity and Access Management (IAM) is essential. IAM enables customers to securely control access to AWS services and resources for their users.

Understanding IAM Roles and Policies

IAM roles are an IAM identity that you can create in your account that has specific permissions. An IAM role is not associated with a specific user or group. Instead, trusted entities assume roles, such as IAM users, applications, or AWS services like EC2. Roles have policies attached to them that grant or deny access to resources.

IAM policies are JSON statements which are used to define the permissions and can be attached to users, groups, or roles. Policies allow you to specify who (the principal) can perform actions on what resources, and under what conditions.

Key Concepts in RBAC

• Principle of least privilege: Users should only have permissions necessary to perform their job.
• Separation of duties: Duties and privileges for a particular job should be divided among multiple individuals.
• Explicit deny: If a permission is not explicitly granted, then access should be denied.

Implementing RBAC in AWS

1. Create Roles and Assign Policies

For example, if you need a role for developers to access S3 buckets, create an IAM role DeveloperS3Access and attach a policy which allows S3 access:

{
“Version”: “2012-10-17”,
“Statement”: [
{
“Effect”: “Allow”,
“Action”: [
“s3:Get*”,
“s3:List*”
],
“Resource”: “*”
}
]
}

2. Assign Users to Roles

Users are never directly given permissions; instead, they assume roles that grant them the necessary permissions. For example, a developer can assume the DeveloperS3Access role to interact with S3.

3. Use Groups for Managing Multiple Users

Instead of attaching policies to individual users, it’s common practice to create IAM groups for sets of users with similar roles and then attach policies to these groups. Users can be added to or removed from groups as needed.

4. Use AWS managed policies for common use-cases

AWS provides managed policies that are preconfigured for many common use cases, like read-only access to all AWS services. These can be used as a starting point for creating customized roles.

RBAC vs. ABAC

While RBAC focuses on roles and groups, AWS also supports Attribute-Based Access Control (ABAC). ABAC uses tags attached to users and AWS resources. Policies can allow or deny actions based on matching tags, which can provide finer-grained access control. Here’s a simplified comparison:

Practical Example

Imagine an application deployed using AWS services that requires multiple team members to interact with it. Developers may need access to Amazon S3 and DynamoDB to store application data and logs, while DevOps teams require permissions to manage the AWS infrastructure, such as EC2 instances or RDS databases.

For the Developers:

1. Create an IAM role DeveloperRole with required permissions for S3 and DynamoDB.
2. Create an IAM group Developers and assign the DeveloperRole to this group.
3. Add individual developer IAM accounts to the Developers group.

For the DevOps:

1. Create an IAM role DevOpsRole with broader permissions required for EC2, RDS, etc.
2. Create an IAM group DevOps and assign the DevOpsRole to this group.
3. Add individual DevOps IAM accounts to the DevOps group.

This distinction ensures that developers have enough access to complete their tasks without having the capability to alter the core infrastructure, adhering to the principle of least privilege and effectively implementing RBAC.

Understanding and correctly implementing RBAC in AWS is fundamental for both securing AWS resources and passing the AWS Certified Developer – Associate exam. Candidates are expected to demonstrate their ability to manage user identity and access within the AWS platform effectively.