AWS Identity and Access Management (IAM) Roles Anywhere now provides the capability to define a set of mapping rules, allowing you to specify which data is extracted from your X.509 end-entity certificates. The data that is mapped is referred to as attributes and used as session tags in the IAM policy condition in order to allow or deny permissions. These attributes can be in one of the subject, issuer, or subject alternative name (SAN) fields of the X.509 certificate.
Source:: Amazon AWS