So it looks like you're talking about the base vFiler (i.e. vfiler0) in 7-mode. To see what the effective export policy is for the root (vol0) run the following from the CLI:
and you should get something that includes:
Anyway, it sounds like access to the root is open to public. To verify the configuration run:
FilerName> rdfile /etc/exports
Modify the file to lock it down accordingly (i.e. just have it exported to just your admin host) and then run the following:
FilerName> exportfs -r
That should enforce the new config. Run another exportfs to confirm.
Hope that helps,