Which solution will meet these requirements with the LEAST management overhead?
Use an AWS Systems Manager Parameter Store SecureString parameter that uses an AWS Key Management Service (AWS KMS) AWS managed key to store the access token. Add a resource-based policy to the parameter to allow access from other accounts. Update the IAM role of the EC2 instances with permissions to access Parameter Store. Retrieve the token from Parameter Store with the decrypt flag enabled. Use the decrypted access token to send the message to the chat.
Encrypt the access token by using an AWS Key Management Service (AWS KMS) customer managed key. Store the access token in an Amazon DynamoDB table. Update the IAM role of the EC2 instances with permissions to access DynamoDB and AWS KMS. Retrieve the token from DynamoDDecrypt the token by using AWS KMS on the EC2 instances. Use the decrypted access token to send the message to the chat.
Use AWS Secrets Manager with an AWS Key Management Service (AWS KMS) customer managed key to store the access token. Add a resource-based policy to the secret to allow access from other accounts. Update the IAM role of the EC2 instances with permissions to access Secrets Manager. Retrieve the token from Secrets Manager. Use the decrypted access token to send the message to the chat.
Encrypt the access token by using an AWS Key Management Service (AWS KMS) AWS managed key. Store the access token in an Amazon S3 bucket. Add a bucket policy to the S3 bucket to allow access from other accounts. Update the IAM role of the EC2 instances with permissions to access Amazon S3 and AWS KMS. Retrieve the token from the S3 bucket. Decrypt the token by using AWS KMS on the EC2 instances. Use the decrypted access token to send the massage to the chat.
Explanations:
While AWS Systems Manager Parameter Store can store parameters securely and access can be granted to other accounts, it is generally less suitable for cross-account access compared to AWS Secrets Manager, which is specifically designed for managing secrets. Additionally, the management overhead for using resource-based policies may increase complexity.
Storing the access token in Amazon DynamoDB requires the developer to manage encryption and access controls, increasing management overhead. Although AWS KMS provides encryption at rest and transit, managing permissions and decryption on the EC2 instances introduces additional complexity compared to using a service designed specifically for secret management.
AWS Secrets Manager is purpose-built for storing sensitive information like access tokens and provides built-in support for encryption at rest and in transit. It also allows for easy cross-account access through resource-based policies, minimizing management overhead while ensuring security requirements are met.
Storing the access token in an S3 bucket requires additional management of bucket policies and encryption. While it can be secured using AWS KMS, the complexity of managing S3 access and ensuring compliance with security best practices makes it less optimal compared to AWS Secrets Manager.
I design that the answer is:
Use AWS Secrets Manager with an AWS Key Management Service (AWS KMS) customer managed key to store the access token. Add a resource-based policy to the secret to allow access from other accounts. Update the IAM role of the EC2 instances with permissions to access Secrets Manager. Retrieve the token from Secrets Manager. Use the decrypted access token to send the message to the chat.