can you put iam keys in lambda environment variables

2 min read 23-01-2025

can you put iam keys in lambda environment variables

Short Answer: No, you should absolutely not store IAM access keys directly in AWS Lambda environment variables. This is a major security risk.

This article explores why storing IAM keys in Lambda environment variables is a terrible idea and outlines safer alternatives for granting your Lambda functions access to AWS resources.

Why Storing IAM Keys in Environment Variables is Insecure

Placing your IAM access keys directly into Lambda environment variables introduces significant security vulnerabilities:

Compromised Credentials: If your Lambda function's code or the environment it runs in is compromised, an attacker gains direct access to your IAM credentials. This allows them to perform actions on your AWS account with the privileges granted to those keys.
Accidental Exposure: Environment variables, while generally less visible than code, are still accessible through various means, including debugging tools or misconfigurations. Accidental exposure leads to the same consequences as a direct compromise.
Violation of Security Best Practices: Storing credentials directly in code or environment variables is a fundamental violation of cloud security best practices. It drastically increases your attack surface.
Difficult Auditing: Tracking who accessed and used those keys becomes extremely difficult, making security auditing and incident response significantly harder.

Secure Alternatives for Accessing AWS Resources

Fortunately, far safer methods exist to allow your Lambda functions to interact with other AWS services:

1. IAM Roles

This is the recommended approach. Instead of using access keys, configure an IAM role for your Lambda function. This role defines the specific permissions your function needs to access other AWS resources. Lambda automatically assumes this role when executing, providing temporary, limited-privilege credentials.

How it works: When you create your Lambda function, you associate it with an IAM role. This role grants the function only the necessary permissions, adhering to the principle of least privilege.

Advantages: Enhanced security, streamlined management, easier auditing, and no need to manage or rotate access keys.

2. AWS Secrets Manager

If you absolutely must use secrets (though IAM roles are almost always preferable), store them securely in AWS Secrets Manager. Your Lambda function can then retrieve these secrets at runtime using the AWS SDK. This approach still requires careful handling, but offers more security than environment variables.

Advantages: Centralized secret management, encryption at rest and in transit, and robust access control.
Disadvantages: Adds complexity compared to IAM roles. Requires careful configuration and access control management.

3. AssumeRole API Call

For more complex scenarios, use the AssumeRole API call within your Lambda function. This allows your function to assume a specific role temporarily, gaining the necessary permissions for a particular task. This is useful for functions needing different permissions depending on their actions.

Best Practices for Secure Lambda Functions

Beyond the choice of credential management, follow these security best practices:

Principle of Least Privilege: Grant your Lambda functions only the minimum necessary permissions to perform their tasks. Avoid overly permissive roles.
Regular Security Audits: Regularly review your Lambda function's IAM roles and permissions to ensure they remain appropriate.
Code Security: Follow secure coding practices to protect against vulnerabilities in your function's code.
Monitoring: Implement monitoring and logging to detect any unusual activity or potential security breaches.

Conclusion: Prioritize Security

Never store IAM access keys directly in Lambda environment variables. The security risks are too substantial. Employ IAM roles as the primary method for granting access to AWS resources, leveraging Secrets Manager only when absolutely necessary and with extreme caution. Prioritize security best practices throughout your Lambda function's lifecycle to protect your AWS account. Remember, security is an ongoing process, not a one-time task.