Introduction

Configuration data management and secrets management platforms or services exist to address several critical challenges in managing sensitive information and application settings in modern, complex IT environments. These challenges stem from the evolving nature of software development, deployment, and operations. It is a widely adopted practice to centralize security controls alongside regulatory or compliance requirements.

As organizations increasingly rely on cloud services, the challenge of securely managing sensitive information—such as API keys, database credentials, and application configuration—has become paramount.  This is where secrets management platforms like AWS Systems Manager Parameter Store and AWS Secrets Manager come into play. These services simplify the process, ensuring that sensitive data is stored securely, accessed safely, and managed efficiently. But what are the differences between these two services, and when should you choose one over the other? Let’s find out!

Understanding the Basics

AWS Systems Manager Parameter Store:

AWS Systems Manager's Parameter Store offers a secure, hierarchical system for managing configuration data and secrets. It allows you to store various types of information, including passwords, database connection strings, AMI IDs, and license codes as parameter values. These values can be saved in plain text or encrypted format. By assigning unique names to parameters when you create them, you can easily reference them in your scripts, commands and various workflows for configuration and automation tasks.

AWS Secrets Manager:

Conversely, AWS Secrets Manager is a dedicated service for managing sensitive information, such as database credentials and API keys. It automates the rotation of secrets, ensuring that sensitive data remains secure and up-to-date. Secrets Manager is particularly advantageous for applications requiring strict security measures, leveraging AWS services to enhance security and compliance.

Where They Overlap

Managed key/value store:

• With both services, you can store values under a name or key.

Encryption:

• With both, you can use AWS KMS to encrypt values.

CloudFormation Integration:

• Both can be referenced in a CloudFormation template.

Versioning:

• With both, you can view or restore older versions of your parameter or secret.

Where They Differ

Automatic secret rotation with Amazon Relational Database Service (Amazon RDS):

• Secrets Manager provides full key rotation integration with Amazon RDS.
• Parameter Store can notify you of expiring secrets but cannot rotate them

Random secret generation:

• Secrets Manager can randomly generate passwords in CloudFormation and store the password in Secrets Manager.

Sharing secrets:

• Secrets Manager has native support for sharing secrets across AWS accounts.
• Parameter Store requires additional configuration.

Resource-based policies:

• Secrets Manager supports resource-based policies for fine-grained access control.
• Parameter Store relies on IAM policies for access control.

Maximum size of secrets/parameters:

• Secrets Manager supports up to 65,536 bytes.
• Parameter Store standard parameters support up to 4,096 bytes and advanced parameters support up to 8,192 bytes.

Cost:

• Secrets Manager can exceed 10,000 parameters, but has costs associated with the storage of secrets and API calls.
• Parameter Store comes with no additional cost with a limit of 10,000 parameters.

Comparing AWS Systems Manager Parameter Store & AWS Secrets Manager

Ease of Use

Both services offer intuitive interfaces and are integrated with AWS Identity and Access Management (IAM) for access control. Parameter Store is often seen as more flexible due to its ability to store both encrypted and plaintext data, making it easier to manage a wider variety of configuration data. However, Secrets Manager edges out in scenarios requiring automated secret rotation, simplifying management for users focused on security.

Maturity and Features

Both services share common features such as encryption via AWS Key Management Service (KMS) and support for versioning. However, Secrets Manager has a more mature feature set tailored specifically for secret management, including automatic secret rotation and a built-in password generator. Parameter Store, while versatile, is primarily designed for broader configuration management, which may limit its capabilities in specialized secret management scenarios.

Scalability

AWS Secrets Manager is designed to handle high volumes of secrets and can automatically scale to meet demand. It supports up to 64KB per secret, while Parameter Store allows for 4KB per standard parameter and 8KB per advanced parameter. For organizations anticipating rapid growth or requiring extensive secret management, Secrets Manager is often the preferred choice due to its scalability and robust features.

Cost-Effectiveness

Parameter Store is generally more cost-effective, especially for organizations with basic needs. It is priced on 2 dimensions: Storage and API interactions. It allows for up to 10,000 standard parameters to be stored at no charge, making it an attractive option for managing configuration data. There are no charges for the standard API interactions when throughput is low but it costs $0.05 per 10,000 Parameter Store API interactions for high throughput.

For advanced parameter types, it costs $0.05 per advanced parameter per month for storage.  And $0.05 per 10,000 Parameter Store API interactions for both standard and higher throughput requests.

Alternatives

For other types of secrets you might have in your organization, AWS recommends you use the following services:

• AWS Identity and Access Management for AWS credentials.
• AWS Key Management Service for Encryption keys.
• Amazon EC2 Instance Connect for SSH keys.
• AWS Certificate Manager for private keys and certificates.

For third-party secret management, HashiCorp Vault is a popular option to consider.

Conclusion

Choosing between AWS Systems Manager Parameter Store and AWS Secrets Manager is a false dichotomy. You shouldn’t draw the line because they have overlapping features. Using both services together provides a powerful, flexible, and secure approach to managing both configuration data and secrets in your cloud environment. By leveraging the strengths of each service, you can ensure that your applications are secure, scalable, and easy to manage, all while maintaining a clear separation of concerns and simplifying your infrastructure management processes. For example, you use Parameter Store to store non-sensitive data like the API base URLs, feature toggles, and environment-specific variables and Secrets Manager to store the API keys, database credentials, and other sensitive information that require regular rotation.

Understanding the functionalities and costs of each service will help tailor your approach to secrets management in the AWS cloud, aligning with your security policies and operational requirements.

References

AWS Systems Manager Parameter Store - AWS Systems Manager

Cloud Password Management, Credential Storage - AWS Secrets Manager - AWS

Pricing | AWS Secrets Manager | Amazon Web Services (AWS)

Centralized Operations Hub – AWS Systems Manager Pricing – Amazon Web Services