Share permissions set the maximum allowable actions available within a shared folder. By default, when you create a share, everyone with access to the network has Read access to the share’s contents. This is an important security change—in previous editions the default permission was Full Control.
With NTFS volumes you can use file and folder permissions and ownership to further constrain actions within the share as well as share permissions. With file allocation table (FAT) volumes, share permissions provide only access controls.
From the most restrictive to the least restrictive, the share permissions available are:
No Access. No permissions are granted for the share.
Read. With this permission, ...