AWS IAM Best Practices: Secure Your Cloud


This article provides an in-depth guide to AWS IAM best practices, helping you secure and optimize your cloud environment.

Understanding AWS IAM

AWS IAM is a robust security service from AWS that helps you securely control access to AWS resources. It allows you to control who is authenticated (signed in) and authorized (has permissions) to use resources. The key components of IAM include Users, Groups, Roles, and Policies. Understanding these components is crucial for effectively managing access to your AWS resources.  For a deeper dive into cloud security, check out our Cloud Security guide.

AWS IAM Basic Setup Best Practices

Principle of Least Privilege

The principle of least privilege (PoLP) is a computer security concept in which a user is given the minimum levels of access necessary to complete his/her job functions. In IAM, this means granting only the permissions required to perform a task. Implementing PoLP helps to reduce the ‘attack surface’ and potential damage from accidents or errors.

To implement PoLP, start by creating IAM users with no permissions. Then, grant only the permissions required to perform their tasks. You can do this by attaching policies to the IAM user that grant only the necessary permissions.

Use IAM Groups to Assign Permissions

IAM groups are a way of managing multiple users that need the same set of permissions. Instead of defining permissions for individual IAM users, it’s usually more convenient to create groups that represent job functions (roles), define the relevant permissions for each group, and then assign IAM users to those groups.

To use IAM groups effectively, first, identify the job functions in your organization. Then, create an IAM group for each job function and assign the necessary permissions to each group. Finally, add IAM users to the groups that correspond to their job functions.

Implement Strong Password Policies

Strong password policies are crucial for the security of your AWS resources. AWS allows you to enforce password complexity, expiration, and history requirements. For example, you can require that passwords include a mix of uppercase letters, lowercase letters, numbers, and special characters.

To implement strong password policies in AWS IAM, go to the IAM dashboard in the AWS Management Console, and then choose “Account Settings”. Here, you can define your password policy.

AWS IAM Security Best Practices

Enable Multi-Factor Authentication (MFA)

MFA adds an extra layer of protection on top of your username and password. With MFA enabled, when a user signs in to an AWS website, they will be prompted for their username and password (the first factor—what they know), and then, for an authentication code from their AWS MFA device (the second factor—what they have). Users can use a mobile app or hardware MFA device for this purpose.

To enable MFA, go to the IAM dashboard in the AWS Management Console, choose “Users”, select a user, and then choose the “Security Credentials” tab. Here, you can manage MFA.

Regularly Rotate and Remove Unused Credentials

Rotating credentials regularly and removing unused credentials helps to reduce the risk of old or unnecessary credentials being used to gain unauthorized access. AWS provides the IAM credential report that lists all your IAM users and the status of their various credentials.

To rotate IAM credentials, first, create new access keys for the IAM user, then update all applications to use the new access keys, and finally, delete the old access keys. To remove unused credentials, you can use the IAM credential report to identify unused credentials and then delete them.

Use IAM Roles Instead of Sharing Credentials

IAM roles provide a secure way to delegate permissions without sharing long-term credentials. Roles can be assumed by trusted entities, such as IAM users, applications, or AWS services like EC2.

To use IAM roles, first, create a role by choosing “Roles” in the IAM dashboard and then “Create role”. Specify the trusted entity (like an AWS service), attach the necessary policies, and then review and create the role. Then, you can specify this role when launching an EC2 instance or configuring a service.

AWS IAM Advanced Setup Best Practices

Use IAM Roles for Applications That Run on Amazon EC2 Instances

When you launch an EC2 instance, you can specify an IAM role to associate with the instance. Any applications or processes that run on the instance can then use the role’s credentials to access AWS services. This eliminates the need to share or embed long-term AWS security credentials with your applications.

To use IAM roles for EC2 instances, first, create an IAM role with the necessary permissions. Then, when launching an EC2 instance, specify this role in the “Configure Instance Details” step.

Monitor Activity in Your AWS Account

Monitoring activity in your AWS account is an important part of maintaining a secure environment. AWS provides several tools for monitoring, including AWS CloudTrail, which logs API calls made in your AWS account, and AWS Config, which provides a comprehensive view of the configuration of AWS resources in your AWS account. For more on monitoring, check out our IDS/IPS on AWS article.

To set up monitoring, first, enable AWS CloudTrail in the AWS Management Console. Then, configure AWS Config to record all resource types and deliver configuration changes.

Use Service Control Policies (SCPs) for Additional Security

Service Control Policies or SCPs are a type of policy that you can use to manage permissions in your AWS organization. SCPs offer central control over the maximum available permissions for all accounts in your organization, allowing you to ensure your accounts stay within your organization’s access control & security governance guidelines.

To use SCPs, go to the AWS Organizations page in the AWS Management Console, choose “Policies”, and then “Create policy”. Here, you can create an SCP and attach it to your organization or organizational units.

AWS IAM Automation Best Practices

Automate IAM Policy Creation

Automating IAM policy creation can help reduce human error and increase efficiency. AWS provides tools like AWS CloudFormation and AWS Managed Policies to help with this.

To automate IAM policy creation, you can use AWS CloudFormation to create a stack that includes IAM policies. Alternatively, you can use AWS Managed Policies, which are IAM policies that AWS creates and manages for you.

Use AWS IAM Access Analyzer

AWS IAM Access Analyzer helps you identify resources in your organization and accounts, such as Amazon S3 buckets or IAM roles, that are shared with an entity outside of your account. This can help you identify unintended access to your resources and data.

To use AWS IAM Access Analyzer, go to the IAM dashboard in the AWS Management Console, choose “Access Analyzer”, and then “Create analyzer”. Here, you can create an analyzer for your account or organization.


Implementing these AWS IAM best practices can significantly enhance the security and efficiency of your AWS environment. Remember, security is a continuous process and requires regular review and updates. For more on AWS security, check out our AWS EC2 Security: Security Group Facts article.