Information
Only allow explicitly defined host access to NFS exported filesystems and directories.
Rationale:
The NFS server should be configured to only allow explicitly defined hosts to mount filesystems from the server. If an unauthorized host is denied the permission to mount a filesystem, then the unauthorized users on that host will not be able to access the server's files.
The default value of access allows any machine to mount any exported filesystems/directories.
Solution
Ensure that all exports defined in /etc/exports have explicit client access options which clearly define the host or hosts allowed access: Review the content of /etc/exports and that all exports have explicit access lists:
showmount -e | grep '(everyone)'
Ensure that each NFS export has an explicit access line, for example, modify:
/export/repo (everyone)
to:
/export/repo x071
The option -c is used to specify clients permitted access:
chnfsexp -d /export/repo -c x071
Default Value:
N/A
Additional Information:
Reversion: Clear the client access specification by supplying the NULL string ('') as argument.
chnfsexp -d /export/repo -c ''