Users, Roles, and Permissions are the backbone of any IAM system.
Users: The Individuals Behind the Actions
Users represent real people or systems interacting with your resources. Each user is typically associated with a unique identifier (e.g., username, email) and credentials (e.g., password, SSH keys).
In IAM, users are the entities to whom you grant permissions. However, directly assigning permissions to individual users can become unwieldy as your system grows. That’s where roles come into play.
Roles: Bundles of Permissions for Flexibility
Roles are collections of permissions that define what actions a user can perform on specific resources. Instead of assigning permissions directly to users, you assign roles to users. This approach offers several advantages:
- Simplified Management: Roles allow you to manage permissions centrally. Instead of modifying individual user permissions, you update the role, and all users assigned to that role inherit the changes.
- Scalability: As your organization grows, roles make it easier to onboard new users and assign appropriate permissions without manually configuring each user.
- Flexibility: You can create roles tailored to different job functions or responsibilities within your organization. For example, you might have roles like “Administrator,” “Developer,” or “Read-Only User.”
Permissions: Fine-Grained Access Control
Permissions are the most granular level of access control in IAM. They specify the actions that a user or role is allowed to perform on a particular resource. Permissions can be highly specific, such as “read,” “write,” “delete,” or more complex actions like “start instance” or “create database.”
IAM systems often provide a way to define fine-grained permissions using a combination of actions and resources. For example, a permission might be expressed as “s3:GetObject” (read objects from S3 buckets) or “ec2:StartInstances” (start EC2 instances).
Combining Users, Roles, and Permissions
Generally, these three roles come together like this:
- Create Roles: Define roles that represent different job functions or responsibilities within your organization.
- Assign Permissions to Roles: Associate specific permissions with each role, defining the actions that users with that role can perform.
- Assign Roles to Users: Assign roles to individual users based on their job function or responsibilities.
This approach ensures that users have the necessary access to perform their tasks without granting them excessive permissions that could pose security risks.
You need to know: The Least Privilege Principle
A fundamental principle in IAM is the principle of least privilege. This principle states that users should be granted only the minimum permissions necessary to perform their jobs. Adhering to this principle minimizes the risk of unauthorized access and data breaches.