Requirement Analysis: The Lambda function in the administrator account needs to process messages from an SNS topic in the production account.

IAM Policy for SNS Topic: Allows the Lambda function to subscribe and be invoked by the SNS topic.

SQS Queue for Buffering: Using an SQS queue provides reliable message delivery and buffering between SNS and Lambda, ensuring all messages are processed.

Implementation:

Create an SQS queue in the administrator account.

Set an IAM policy to allow the Lambda function to subscribe to and be invoked by the SNS topic.

Configure the SNS topic to send messages to the SQS queue.

Set up the SQS queue to trigger the Lambda function.

Conclusion: This solution ensures reliable message delivery and processing with appropriate permissions.

References

Amazon SNS:Amazon SNS Documentation

Amazon SQS:Amazon SQS Documentation

AWS Lambda:AWS Lambda Documentation