AWS IAM Access Management Guide | Generated by AI
AWS Identity and Access Management (IAM) is a free service that helps you securely control access to AWS resources. It enables you to manage users and their permissions, ensuring that the right people and applications have the appropriate access to the right resources. IAM handles authentication (who can sign in) and authorization (what actions they can perform).
Core Components of IAM
- Users: Represent individuals or applications that need access to AWS. Each user has unique security credentials (e.g., passwords or access keys).
- Groups: Collections of users for easier permission management. Permissions are attached to groups, not individual users directly.
- Roles: Temporary identities with permissions that can be assumed by users, services, or applications. Roles don’t have permanent credentials; they provide short-lived security tokens.
- Policies: JSON documents that define permissions. They specify actions (e.g., read, write), resources (e.g., S3 buckets), and conditions (e.g., IP restrictions). There are AWS-managed, customer-managed, and inline policies.
Getting Started: Step-by-Step Guide
Prerequisites
- Sign in to the AWS Management Console as the root user (your account’s email and password). Important: Avoid using the root user for daily tasks—create an admin user immediately.
- Enable multi-factor authentication (MFA) for the root user for added security.
1. Create an IAM User
Use the AWS Management Console for simplicity (CLI or API options are available for automation).
- Open the IAM console at https://console.aws.amazon.com/iam/.
- In the navigation pane, choose Users > Create user.
- Enter a user name (e.g., “admin-user”) and select Next.
- Under Set permissions, choose Attach policies directly and select an AWS-managed policy like “AdministratorAccess” for full access (start with least privilege in production).
- (Optional) Set a console password: Choose Custom password and enable Require password reset.
- Review and choose Create user.
- Provide the user with their sign-in URL (e.g., https://[account-alias].signin.aws.amazon.com/console), user name, and temporary password.
For programmatic access, generate access keys (but prefer roles for applications).
2. Create and Manage Groups
Groups simplify scaling permissions.
- In the IAM console, choose User groups > Create group.
- Enter a group name (e.g., “Developers”).
- Attach policies (e.g., “AmazonEC2ReadOnlyAccess”).
- Choose Create group.
- To add users: Select the group > Add users to group > Choose existing users.
Users inherit all group permissions. A user can belong to multiple groups.
3. Create and Attach Policies
Policies define what actions are allowed.
- Types:
- AWS-managed: Pre-built for common jobs (e.g., “ReadOnlyAccess”).
- Customer-managed: Custom JSON for your needs.
- Inline: Embedded directly in a user/group/role (use sparingly).
To create a custom policy:
- In IAM console, choose Policies > Create policy.
- Use the visual editor or JSON tab (e.g., allow “s3:GetObject” on a specific bucket).
- Name it and choose Create policy.
- Attach it to users/groups/roles via Attach policy.
Best practice: Grant least privilege—start broad, then refine using tools like IAM Access Analyzer.
4. Use IAM Roles
Roles are ideal for temporary access, avoiding long-term credentials.
- In IAM console, choose Roles > Create role.
- Select trusted entity (e.g., “AWS service” for EC2, or “Another AWS account” for cross-account).
- Attach permissions policies.
- Add a trust policy (JSON defining who can assume the role, e.g., EC2 service principal).
- Name it and choose Create role.
Common Scenarios:
- EC2 Instances: Attach a role to an instance for secure access to other services (e.g., S3) without embedding keys.
- Cross-Account Access: In Account A (trusting), create a role with a trust policy allowing principals from Account B. Users in B assume the role via AWS STS to access A’s resources.
Assume a role via console, CLI (aws sts assume-role), or SDKs to get temporary credentials.
5. Enable MFA and Additional Security
- For users: In IAM console > Users > Select user > Security credentials > Manage MFA.
- Use virtual (app-based) or hardware MFA devices.
Best Practices for Security
- Lock Down Root User: Use only for tasks requiring it (e.g., changing account settings). Enable MFA and don’t create access keys.
- Use Temporary Credentials: Prefer federation (e.g., via IAM Identity Center) and roles over long-term keys. Rotate keys if used.
- Principle of Least Privilege: Grant minimal permissions; use conditions (e.g., time/IP limits) in policies.
- Monitor and Audit: Enable AWS CloudTrail, use IAM Access Analyzer to detect unused permissions or unintended access, and review last-used info.
- Remove Unused Resources: Delete inactive users/roles/policies regularly.
- For Multi-Account: Use AWS Organizations with service control policies (SCPs) as guardrails.
- Validate Policies: Use IAM Access Analyzer’s policy checks before applying.
For hands-on learning, explore IAM tutorials in the console or docs for scenarios like attribute-based access control (ABAC).