Can I restrict users from using UNCs?
How can I restrict users from typing in the UNC of our server in Word and WordPerfect and then browsing our server? I know I can restrict hyperlinking, but our users can just turn it back on. Can UNCs be disabled?
There is a registry entry that may help you control this in some versions of Word. For example, if you are using Office 8, Navigate the Windows Registry to
HKEY_CURRENT_USERSsoftwareMicrosoftoffice8.0WordOptions. Add a new DWORD value of DontUseUNC and set it to 1. This turns off the ability to use a entered hyperlink in Word to access a server via a UNC path entry. Test this with your version of Word on a single system, then deploy, as you would any registry change. i.e. with a script, by adding it to a security template and applying the template and so forth. Don't forget to check permissions on the registry key. A sophisticated user can research this on the Microsoft Web site and change the value to 0 unless you protect the key. (By default, only Administrators, the Administrator and SYSTEM have the ability to change settings on the Options key).
More importantly, a sophisticated user can enter a UNC path many other places in Windows and access a server. To stop them you must set permissions appropriately on the server. No matter how the server is accessed, through a mapped drive, command line, Word or other program, if the permissions set on the server do not grant the user access, they will not be able to obtain access using a UNC path. This is really the answer to this question.
This was first published in December 2003