Share this Folder
On a shared (collaborated) folder ensure that the "Share this Folder" option is removed from all external collaborators as testing has shown that it is possible for an external collaborator (even with viewer permissions) to enable sharing and get a copy of the shared link albeit the link defaults to “internal access” only.
3
votes

Thanks for the feedback. Per our collaborator permission guidelines, Viewer permissions are able to see and send view-only shared links — however they cannot invite collaborators or modify sharing permissions.
https://support.box.com/hc/en-us/articles/360044196413-Understanding-Collaborator-Permission-Levels