Can it communicate over https or requires binary protocol? and what are the privileges it requires?
Filebeat can use https. For more details see here: https://www.elastic.co/guide/en/beats/libbeat/current/_https_and_basic_authentication.html
More details on the TLS options can be found here: https://www.elastic.co/guide/en/beats/libbeat/current/configuration.html#configuration-output-tls
Filebeat needs read access to the files you want to be sent.