AWS Identity and Access Management (IAM): Secure Access Control

What is IAM?​

AWS Identity and Access Management (IAM) is a service that helps you manage access to AWS resources securely. Using IAM, you can create and manage AWS users and groups, set permissions to allow or deny their access to AWS resources, and apply policies that specify what actions can be performed.

IAM Policies​

IAM Policies are JSON documents that define permissions. They specify which actions are allowed or denied for users, groups, or roles on specific AWS resources.

Example:

To maintain security and proper management of the NailYourInterview website, you might create a policy named S3ContentManagementPolicy. This policy grants specific permissions like s3:PutObject and s3:GetObject on a particular S3 bucket (e.g., nailyourinterview-images). This policy can be attached to IAM users, groups, or roles, providing them with the necessary access to manage images in the S3 bucket.

IAM Users​

IAM Users are individual entities created in AWS to represent people or applications that need access to AWS resources. Each user has unique credentials and can have specific permissions assigned to them.

Example:

Imagine you have a team member named Bob who is responsible for managing content on the NailYourInterview website, including uploading images to an S3 bucket. Should you give Bob your AWS credentials? Absolutely not! That would be insecure.

Instead, you create an IAM User named Bob. Bob can then log into the AWS Management Console with his unique credentials as an IAM User. By default, IAM Users have no permissions—they cannot see or manage any AWS resources. To allow Bob to upload images, you attach the S3ContentManagementPolicy to his user account, granting him the necessary permissions for the S3 bucket.

IAM Groups​

IAM Groups are collections of IAM Users that simplify permissions management.

Example:

To streamline the management of permissions for multiple team members working on different aspects of the NailYourInterview website, you could create two groups: ContentCreators and DevOps.

• ContentCreators: Members of this group have permissions to access and manage S3 buckets, allowing them to handle content like images and videos.

• DevOps: Members of this group have permissions to manage infrastructure resources like EC2 instances, Elastic Load Balancers (ELBs), and CloudWatch for monitoring.

By attaching relevant policies to these groups, you can easily grant or revoke permissions for all users in a group, saving time and ensuring consistency. If you need to update permissions, you only need to modify the group's policies, and the changes will automatically apply to all members.

IAM Roles​

IAM Roles are sets of permissions that can be assumed by trusted entities, such as AWS services (e.g., EC2), to perform actions on AWS resources. Unlike users, roles do not have long-term credentials like passwords or access keys. Instead, they provide temporary credentials when assumed.

Example:

For NailYourInterview, suppose you have an EC2 instance running a web application that logs visitor interactions and uploads these logs to an S3 bucket for analysis. To securely handle this, you create an IAM Role named EC2LoggingRole with permissions to write logs to the specific S3 bucket (nailyourinterview-logs).

When you launch the EC2 instance, you associate it with the EC2LoggingRole. The instance can then assume this role, automatically gaining temporary credentials that allow it to upload log files to the S3 bucket. This means you don't need to hard-code any sensitive credentials or use .env files to store them. Even if the EC2 instance is compromised, the security of your AWS account remains protected, as the permissions are tightly controlled and the temporary credentials are automatically rotated and expired.

Summary​

AWS IAM is a powerful tool for managing access to your AWS resources securely. By using policies, users, groups, and roles effectively, you can enforce the principle of least privilege, ensuring that each user or application has only the permissions necessary to perform their tasks. This approach minimizes the risk of unauthorized access and helps maintain the security and integrity of your AWS environment.