AWS IAM Best Practices: Security Guide for Cloud Teams (2025)

AWS Identity and Access Management (IAM) is the gatekeeper to your cloud infrastructure. Misconfigured IAM is the #1 cause of cloud security breaches. This guide covers essential security practices.

IAM Fundamentals

Users - Individual people or services
Groups - Collections of users
Roles - Temporary credentials for services
Policies - JSON documents defining permissions

The Principle of Least Privilege

Grant only the permissions required to perform a task. Start with zero permissions and add only what's needed. This is the most important IAM principle.

Essential Best Practices

1. Never Use Root Account

Create IAM users for daily tasks. Enable MFA on root, lock away credentials, and only use for account-level tasks like closing the account.

2. Enable MFA Everywhere

Require multi-factor authentication for all IAM users, especially those with console access or admin privileges.

3. Use Roles, Not Long-Term Keys

For applications and services, use IAM roles instead of access keys. Roles provide temporary credentials that rotate automatically.

4. Implement SCPs for Organizations

Service Control Policies set permission guardrails across your entire organization. Use them to prevent dangerous actions like disabling CloudTrail.

Policy Examples

Example read-only S3 policy: {"Effect": "Allow", "Action": ["s3:GetObject", "s3:ListBucket"], "Resource": ["arn:aws:s3:::mybucket/*"]}

Regular Auditing

Use IAM Access Analyzer to find unused permissions
Review CloudTrail logs for suspicious activity
Generate credential reports monthly
Remove unused users and roles

Need Cloud Security Help?

CloudElevate implements IAM best practices and cloud security frameworks. We help you achieve compliance while maintaining developer productivity.