I have just noticed that in my Plex container, in plex user's home directory, there is a .ssh folder, in which there is a known_hosts file, containing a reference to the following host:
178.79.150.113:443
Is this expected? Does plex use outbound ssh for proxying purposes to work around network routing issues, and if so, is this one of the hosts it uses for proxying? If not, this is concerning because the container only runs plex, no other processes run in it, and the only port the container has available to listen on is 32400.
If this is expected behaviour for plex, it should be documented. If it isn't, it implies there is a remote code execution exploit in plex.
If somebody on plex staff could please clarify, that would be most appreciated.