What is the MOST secure way to resolve this issue?
Update the IAM instance profile that is attached to the EC2 instance to include the S3:* permission for the S3 bucket.
Update the IAM instance profile that is attached to the EC2 instance to include the S3:ListBucket permission for the S3 bucket.
Update the developer’s user permissions to include the S3:ListBucket permission for the S3 bucket.
Update the S3 bucket policy by including the S3:ListBucket permission and by setting the Principal element to specify the account number of the EC2 instance.
Explanations:
GrantingS3:*permission gives excessive access beyond just listing the objects. This violates the principle of least privilege, as it allows more actions than necessary.
Granting theS3:ListBucketpermission specifically allows the application to list the objects in the S3 bucket, providing the least privilege necessary for the application to function correctly.
Updating the developer’s user permissions does not resolve the issue for the application running on the EC2 instance. The application requires permissions attached to the instance profile, not the developer’s permissions.
Modifying the S3 bucket policy may grant access but does not align with best practices. It’s more secure to use IAM roles and instance profiles to manage permissions rather than modifying the bucket policy directly.
I value that the answer is:
Update the IAM instance profile that is attached to the EC2 instance to include the S3:ListBucket permission for the S3 bucket.