Due to performance limitations, standard fields are not listed under the objects. This is done intentionally in order to provide the best user experience for the most common use case of setting security for custom fields. Retrieving the list of standard fields for each object during the connection process would slow down the connection process significantly.
If you want to analyze or deploy security of standard fields, retrieve the object with all fields selected. Retrieving the object with all fields selected will retrieve the following entities related to that object: