Enable AWS Config. Create a proactive AWS Config Custom Policy rule. Create a Guard clause to evaluate the S3 bucket policies to check for a value of True for the aws:SecureTransport condition key. If the AWS Config rule evaluates to NON_COMPLIANT, block resource creation.

Enable AWS Config. Configure the s3-bucket-ssl-requests-only AWS Config managed rule and set the rule trigger type to Hybrid. Create an AWS Systems Manager Automation runbook that applies a bucket policy to deny requests when the value of the aws:SecureTransport condition key is False. Configure automatic remediation. Set the runbook as the target of the rule.

Enable Amazon Inspector. Create a custom AWS Lambda rule. Create a Lambda function that applies a bucket policy to deny requests when the value of the aws:SecureTransport condition key is False. Set the Lambda function as the target of the rule.

Create an AWS CloudTrail trail. Enable S3 data events on the trail. Create an AWS Lambda function that applies a bucket policy to deny requests when the value of the aws:SecureTransport condition key is False. Configure the CloudTrail trail to invoke the Lambda function.