Security best practices for AWS AppSync

Securing AWS AppSync is more than simply turning on a few levers or setting up logging. The following sections discuss security best practices that vary depending on how you use the service.

Understand authentication methods

AWS AppSync provides multiple ways to authenticate your users to your GraphQL APIs. Each method has trade-offs in security, auditability, and usability.

The following common authentication methods are available:

• Amazon Cognito user pools allow your GraphQL API to use user attributes for fine-grained access control and filtering.

• API tokens have a limited lifetime and are appropriate for automated systems, such as Continuous Integration systems and integration with external APIs.

• AWS Identity and Access Management (IAM) is appropriate for internal applications managed in your AWS account.

• OpenID Connect allows you to control and federate access with the OpenID Connect protocol.

For more information on authentication and authorization in AWS AppSync, see Authorization and authentication.

Use TLS for HTTP resolvers

When using HTTP resolvers, make sure to use TLS-secured (HTTPS) connections wherever possible. For a full list of the TLS certificates that AWS AppSync trusts, see Certificate Authorities (CA) Recognized by AWS AppSync for HTTPS Endpoints.

Use roles with the least permissions possible

When using resolvers such as the DynamoDB resolver, use roles that provide the most restrictive view to your resources, such as your Amazon DynamoDB tables.

IAM policy best practices

Identity-based policies determine whether someone can create, access, or delete AWS AppSync resources in your account. These actions can incur costs for your AWS account. When you create or edit identity-based policies, follow these guidelines and recommendations:

• Get started with AWS managed policies and move toward least-privilege permissions – To get started granting permissions to your users and workloads, use the AWS managed policies that grant permissions for many common use cases. They are available in your AWS account. We recommend that you reduce permissions further by defining AWS customer managed policies that are specific to your use cases. For more information, see AWS managed policies or AWS managed policies for job functions in the IAM User Guide.

• Apply least-privilege permissions – When you set permissions with IAM policies, grant only the permissions required to perform a task. You do this by defining the actions that can be taken on specific resources under specific conditions, also known as least-privilege permissions. For more information about using IAM to apply permissions, see Policies and permissions in IAM in the IAM User Guide.

• Use conditions in IAM policies to further restrict access – You can add a condition to your policies to limit access to actions and resources. For example, you can write a policy condition to specify that all requests must be sent using SSL. You can also use conditions to grant access to service actions if they are used through a specific AWS service, such as AWS CloudFormation. For more information, see IAM JSON policy elements: Condition in the IAM User Guide.

• Use IAM Access Analyzer to validate your IAM policies to ensure secure and functional permissions – IAM Access Analyzer validates new and existing policies so that the policies adhere to the IAM policy language (JSON) and IAM best practices. IAM Access Analyzer provides more than 100 policy checks and actionable recommendations to help you author secure and functional policies. For more information, see IAM Access Analyzer policy validation in the IAM User Guide.

• Require multi-factor authentication (MFA) – If you have a scenario that requires IAM users or a root user in your AWS account, turn on MFA for additional security. To require MFA when API operations are called, add MFA conditions to your policies. For more information, see Configuring MFA-protected API access in the IAM User Guide.

For more information about best practices in IAM, see Security best practices in IAM in the IAM User Guide.