Ensure IAM Policy does not Allow with NotPrincipal

Using "Effect": "Allow" with the NotPrincipal can be overly permissive. For example, this can grant permissions to anonymous principals. AWS recommends that you specify principals that need access using the Principal element.

In AWS Console -

1. Sign in to the AWS console and go to the IAM console.
2. In the Navigation pane, select Policies.
3. In the list of policies, select the policy to edit.
4. Select the Permissions tab, and then choose Edit policy.
5. On the review page, review the changes and click Save.

In Terraform -

1. In the aws_iam_policy resource, edit the policy field so that the allowed Action list and/or Principal have appropriate values rather than setting NotPrincipal.
2. Update the Resource ARN list to use specific IDs rather than a wildcard.
   For more information on how to effectively write an IAM policy see the AWS and Terraform documentation.

References:
https://docs.aws.amazon.com/IAM/latest/UserGuide/service_code_examples_iam.html
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_policy