AWS Identity and Access Management (IAM) enables you to securely control access to AWS services and resources for your users. Using IAM, you can create and manage AWS users and groups, and use permissions to allow and deny their access to AWS resources. The S3 Connector uses AWS IAM’s roles to ensure fine-grained control over access to the content stored in the S3 bucket.
In order to use IAM roles, instead of AWS secret and access keys, a new policy must be created that will be used by the IAM role. Policies are used to grant permissions to groups. If there isn’t a policy already in place for S3 access, a new policy must be created.