Buffer Overflow Vulnerability in Microsoft IIS 5.0

Original release date: May 02, 2001
Last revised: --
Source: CERT/CC

A complete revision history is at the end of this file.

Systems Affected

  • Systems running Microsoft Windows 2000 with IIS 5.0 enabled


A vulnerability exists in Microsoft IIS 5.0 running on Windows 2000 that allows a remote intruder to run arbitrary code on the victim machine, allowing them to gain complete administrative control of the machine.

A proof-of-concept exploit is publicly available for this vulnerability, which increases the urgency that system administrators apply the patch.

I. Description

Windows 2000 includes support for the Internet Printing Protocol (IPP) via an ISAPI extension. According to Microsoft, this extension is installed by default on all Windows 2000 systems, but it is only accesible through IIS 5.0. The IPP extension contains a buffer overflow that could be used by an attacker to execute arbitrary code in the Local System security context, essentially giving the attacker compete control of the system. This vulnerability was discovered by eEye Digital Security.

Microsoft has issued the following bulletin regarding this vulnerability:


This vulnerability has been assigned the identifier CAN-2001-0241 by the Common Vulnerabilities and Exposures (CVE) group:


II. Impact

Anyone who can reach a vulnerable web server can execute arbitrary code in the Local System security context, resulting in the intruder gaining complete control of the system. Note that this may be significantly more serious than a simple "web defacement."

III. Solution

Apply a patch from your vendor

A patch is available from Microsoft at


Additional advice on securing IIS web servers is available from

http://www.microsoft.com/technet/security/iis5chk.asp http://www.microsoft.com/technet/security/tools.asp

Appendix A. Vendor Information

Microsoft Corporation

The following documents regarding this vulnerability are available from Microsoft:



  1. VU#516648: Microsoft Windows 2000/Internet Information Server (IIS) 5.0 Internet Printing Protocol (IPP) ISAPI contains buffer overflow, CERT/CC, 05/02/2001, http://www.kb.cert.org/vuls/id/516648
Authors:  Chad Dougherty, Shawn Hernan.

Copyright 2001 Carnegie Mellon University.

Revision History

May 02, 2001: Initial Release