If your company runs applications on on-premises servers but uses AWS for cloud storage, databases, or other services, you need a secure way to authenticate those servers.
Traditionally, developers have used AWS access keys stored in configuration files or environment variables. However, long-lived access keys can become a security risk if they are leaked, forgotten, or exposed through application logs.
AWS IAM Roles Anywhere provides a more secure alternative. It allows applications running outside AWS, including on-premises servers and private data centers, to obtain temporary AWS credentials using X.509 certificates.
In this guide, you’ll learn how IAM Roles Anywhere works, how to configure it, and why it can help improve AWS security.
What Is AWS IAM Roles Anywhere?
AWS IAM Roles Anywhere is a service that allows workloads running outside AWS to access AWS resources without requiring permanent IAM access keys.
Instead of storing long-lived credentials on your server, you configure a trust relationship between AWS and a certificate authority (CA). Your server uses an X.509 certificate and its corresponding private key to authenticate and request temporary credentials for an IAM role.
These temporary credentials can then be used with supported AWS services, such as Amazon S3.
Why Avoid Long-Lived AWS Access Keys?
Long-lived access keys can create several security challenges:
- Credentials may accidentally be committed to Git repositories.
- Keys can remain active long after a project or employee no longer needs them.
- Rotating keys across multiple servers can become difficult.
- A compromised server may expose credentials that remain valid until revoked or disabled.
IAM Roles Anywhere helps reduce these risks by issuing temporary credentials that expire instead of relying on permanent access keys.
How IAM Roles Anywhere Works
The authentication process involves a few important components:
- X.509 certificate: Identifies the on-premises workload.
- Trust anchor: Connects IAM Roles Anywhere to a trusted certificate authority.
- IAM role: Defines which AWS resources the workload can access.
- Profile: Specifies the IAM roles available to authenticated workloads.
- Temporary credentials: Allow the workload to make authorized AWS API requests.
The server signs a request using its certificate and private key. IAM Roles Anywhere validates the request and certificate, checks the configured trust and permissions, and returns temporary AWS credentials.
These credentials are then used to access AWS resources according to the IAM role’s permissions.
How to Configure AWS IAM Roles Anywhere
Before starting, make sure you have an AWS account, an on-premises Linux server, and a certificate issued by a certificate authority trusted by your organization.
Step 1: Create an IAM Role
Open the AWS IAM console and create a role for IAM Roles Anywhere.
Configure the role’s trust policy to allow the IAM Roles Anywhere service to assume it. Attach only the permissions required by your application.
For example, if your server only needs to upload files to one S3 bucket, avoid granting unrestricted access to all S3 resources.
Step 2: Configure a Trust Anchor
In the IAM Roles Anywhere console, create a trust anchor using your certificate authority.
The trust anchor tells AWS which CA it should trust when validating certificates presented by external workloads.
Use a trusted CA and establish a process for issuing, renewing, and revoking workload certificates.
Step 3: Create an IAM Roles Anywhere Profile
Create a profile and associate it with the IAM role you configured.
The profile determines which roles an authenticated workload can request. Configure it to expose only the roles and permissions required for the intended workload.
Step 4: Install the Signing Helper
AWS provides the IAM Roles Anywhere credential helper, which can obtain temporary credentials for compatible AWS CLI and SDK workflows.
Install the helper on your on-premises server by following the official AWS documentation for your operating system and architecture.
Keep the helper updated and obtain it from an official, trusted source.
Step 5: Configure the Credentials
Prepare the certificate, corresponding private key, trust anchor ARN, profile ARN, and role ARN.
For example, a credentials configuration for the AWS CLI can look like this:
[profile onprem-aws]
region = ap-south-1
credential_process = aws_signing_helper credential-process \
--certificate /etc/aws/certs/server.crt \
--private-key /etc/aws/certs/server.key \
--trust-anchor-arn arn:aws:rolesanywhere:ap-south-1:123456789012:trust-anchor/EXAMPLE \
--profile-arn arn:aws:rolesanywhere:ap-south-1:123456789012:profile/EXAMPLE \
--role-arn arn:aws:iam::123456789012:role/OnPremS3RoleReplace the example ARNs and certificate paths with your actual configuration. Install the AWS CLI and credential helper, and ensure the certificate and private key are readable only by authorized users.
Step 6: Test the AWS Connection
Run the following command to verify that your profile can obtain temporary credentials and access AWS:
aws sts get-caller-identity --profile onprem-awsIf authentication succeeds, AWS returns the identity associated with the assumed role.
You can then test access to a specific AWS resource for which the role has permission.
Best Practices for IAM Roles Anywhere
Follow these security practices when connecting on-premises servers to AWS:
- Use short-lived credentials instead of permanent access keys.
- Apply least-privilege permissions to every IAM role.
- Protect certificate private keys using restrictive file permissions or appropriate hardware-backed key storage.
- Monitor certificate expiration and establish a renewal process.
- Revoke certificates when a server is retired or compromised.
- Enable AWS CloudTrail logging to monitor relevant activity.
- Avoid placing certificates, private keys, or other sensitive material in source control.
- Review IAM trust policies and profile permissions regularly.
Remember that IAM Roles Anywhere reduces reliance on long-lived AWS access keys, but it does not eliminate the need to protect your certificate private keys.
Final Thoughts
AWS IAM Roles Anywhere is a useful option for organizations that need to connect on-premises servers, data centers, or external workloads to AWS securely.
By using certificate-based authentication and temporary AWS credentials, you can reduce the risks associated with long-lived access keys while maintaining controlled access to cloud resources.
If your infrastructure uses both on-premises servers and AWS, IAM Roles Anywhere can help you build a more secure and manageable authentication workflow.
For implementation details and supported configuration options, refer to the official AWS IAM Roles Anywhere documentation.
