Microsoft has posted the Microsoft Windows NT 4.0 and Windows 98 Threat Mitigation Guide

This guide describes how to harden computers that run earlier versions of the Windows operating system. It is appropriate for organizations that have various combinations of computers that run Windows NT 4.0 (Workstation, Server, and Advanced Server) and Windows 98, with or without later versions of Windows clients or servers. This guidance uses a fictitious company scenario (Trey Research) to illustrate how to assess security risks and vulnerabilities in a network infrastructure. It focuses on protective measures you can apply to Windows NT 4.0 and Windows 98 client computers and Windows NT 4.0 servers to improve their security in Active Directory environments.

The Microsoft Windows NT 4.0 and Windows 98 Threat Mitigation Guide