IIS is one of the biggest threats to Windows NT, 2000 and XP security!
You must know how to protect your computer from IIS related attacks, and remember that even though you’re using Windows 2000 Professional – you’re still vulnerable to those attacks (IIS is installed by default on all W2K platforms, but not on XP and Windows Server 2003).
Note: Since IIS is such a potential threat to your system, and since my site is usually NOT security oriented, I cannot guarantee your computer’s safety even if you do follow my recommendations. I cannot be held responsible for anything that might happen to you, your computer, or the information stored on it. I might compile a list of IIS security issues later this month. but till then you can read the TechNet Security Webpage and search for the IIS related issued, and also the Microsoft Security page
IIS 4.0 Required Patches
IIS 4.0 is an optional upgrade to Windows NT 4.0, and can be installed on the machine by installing the Windows NT 4.0 Option Pack.
Internet Information Server (IIS) 4.0 installed on a Windows NT 4.0 SP6a Server box requires the following security-related patches:
This patch is a cumulative patch that includes the functionality of all security patches released for IIS 4.0 since Windows NT 4.0 Service Pack 6a:
327696 MS02-062: October 2002 Cumulative Patch for Internet Information Services
321599 MS02-028: Heap Overrun in HTR Chunked Encoding Might Enable Web Server Compromise
319733 MS02-018: April 2002 Cumulative Patch for Internet Information Services
Other IIS Patching Tools
You should also look at the IIS Lockdown Tool and URLScan which are valuable tools for "anti-IIS" activity protection:
URLScan Security Tool (v2.5) URLscan is a powerful security tool that works in conjunction with the IIS Lockdown Tool to give IIS Web site administrators the ability to turn off unneeded features and restrict the kind of HTTP requests that the server will process. By blocking specific HTTP requests, the URLScan security tool prevents potentially harmful requests from reaching the server and causing damage.
IIS Lockdown Tool (v2.1) IIS Lockdown Wizard works by turning off unnecessary features thereby reducing attack surface available to attackers. To provide defense in depth, or multiple layers of protection against attackers, URLscan, with customized templates for each supported server role, has been integrated into the IIS Lockdown Wizard.