I first discussed Windows Server 2003 Access-based Enumeration (ABE) in tip 9231 ยป Windows Server 2003 SP1 supports Access-Based Enumeration of a shares sub-folders?. That tip also provided a link to a command-line tool to enable ABE.

Microsoft Download Center Windows Server 2003 Access-based Enumeration page contains the following overview:

Windows Server 2003 Access-based Enumeration makes visible only those files or folders that the user has the rights to access. When Access-based Enumeration is enabled, Windows will not display files or folders that the user does not have the rights to access. This download provides a GUI and a CLI that enables this feature.