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===========================================================================
             AUSCERT External Security Bulletin Redistribution

                 ESB-2002.175 -- CERT Advisory CA-2002-09
                 Multiple Vulnerabilities in Microsoft IIS
                               12 April 2002

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:                Internet Information Server 4.0
                        Internet Information Services 5.0
                        Internet Information Services 5.1
Vendor:                 Microsoft
Operating System:       Windows NT
                        Windows 2000
                        Windows XP
Impact:                 Execute Arbitrary Code/Commands
                        Denial of Service
Access Required:        Remote

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CERT Advisory CA-2002-09 Multiple Vulnerabilities in Microsoft IIS

   Original release date: April 11, 2002
   Last revised: --
   Source: CERT/CC

   A complete revision history can be found at the end of this file.

Systems Affected

     * Microsoft IIS 4.0, 5.0, and 5.1

Overview

   A  variety  of  vulnerabilities exist in various versions of Microsoft
   IIS.  Some  of  these vulnerabilities may allow an intruder to execute
   arbitrary code on vulnerable systems.

I. Description

   There are a variety of vulnerabilities in Microsoft IIS. Many of these
   vulnerabilities  are buffer overflows that could permit an intruder to
   execute arbitrary code on vulnerable systems.
   We  strongly  encourage  all  sites  running  IIS  to read Microsoft's
   advisory  on  these  and  other  vulnerabilities  and take appropriate
   action as soon as practical. Microsoft's bulletin is available at

          http://www.microsoft.com/technet/security/bulletin/MS02-018.asp

   Additional information about these vulnerabilities is available at

          http://www.kb.cert.org/vuls


   VU#363715 CAN-2002-0071 Microsoft Internet Information Server (IIS)
             vulnerable to heap overflow during processing of crafted
             ".htr" request by "ISM.DLL" ISAPI filter

   VU#883091 CAN-2002-0074 Microsoft Internet Information Server (IIS)
             contains cross-site scripting vulnerability in IIS Help
             Files search facility

   VU#886699 CAN-2002-0148 Microsoft Internet Information Server (IIS)
             contains cross-site scripting vulnerability in HTTP error
             page results

   VU#520707 CAN-2002-0075 Microsoft Internet Information Server (IIS)
             contains cross-site scripting vulnerability in redirect
             response messages

   VU#412203 CAN-2002-0073 Microsoft Internet Information Server (IIS)
             vulnerable to DoS via malformed FTP connection status
             request

   VU#454091 CAN-2002-0150 Microsoft Internet Information Server (IIS)
             vulnerable to buffer overflow via inaccurate checking of
             delimiters in HTTP header fields

   VU#721963 CAN-2002-0149 Microsoft Internet Information Server (IIS)
             buffer overflow in server-side includes (SSI) containing
             long invalid file name

   VU#521059 CAN-2002-0072 Microsoft Internet Information Server (IIS)
             vulnerable to DoS when URL request exceeds maximum
             allowed length

   VU#610291 CAN-2002-0079 Microsoft Internet Information Server (IIS)
             buffer overflow in chunked encoding transfer mechanism

   VU#669779 CAN-2002-0147 Microsoft Internet Information Server (IIS)
             buffer overflow in chunked encoding transfer mechanism


II. Impact

   For  many  of the vulnerabilities, an intruder could execute arbitrary
   code  with  privileges  that vary according to which version of IIS is
   running.  In general, IIS 4.0 permits an intruder to execute code with
   complete  administrative  privileges,  while IIS 5.0 and 5.1 permit an
   intruder  to execute code with the privileges of the IWAM_computername
   account.

III. Solution

   Microsoft   Corporation   has  released  Microsoft  Security  Bulletin
   MS02-018,  which  announces  the availability of a cumulative patch to
   address  a variety of problems. We strongly encourage you to read this
   bulletin  and  take  the  appropriate corrective measures. MS02-018 is
   available at

          http://www.microsoft.com/technet/security/bulletin/MS02-018.asp

   In  addition  to  applying  the  patch, or until it can be applied, we
   recommend the following actions:

     * Use  the  IIS Lockdown tool and URLScan to eliminate or reduce the
       impact of some of these vulnerabilites; they may also eliminate or
       reduce  other  vulnerabilities  that have not yet been discovered.
       The  IIS Lockdown tool can also be used to disable ASP if it's not
       needed.  More  information about the IIS Lockdown tool and URLScan
       can be found at

          http://www.microsoft.com/technet/security/tools/locktool.asp
                
          http://www.microsoft.com/technet/security/URLScan.asp

     * As  Microsoft has recommended for quite some time, disable the HTR
       ISAPI extension unless it is absolutely required.
     * Disable anonymous FTP unless it is required.
     * Don't give login credentials on IIS servers to untrusted users.
     _________________________________________________________________

   Our  thanks  to Microsoft Corporation for the information contained in
   their advisory. Additionally, our thanks go to the various individuals
   and   organizations  whom  Microsoft  identified  as  discovering  the
   vulnerabilities,       including       eEye      Digital      Security
   (http://www.eeye.com),     Serge     Mister     of    Entrust,    Inc.
   (http://www.entrust.com),       Dave       Aitel       of       @Stake
   (http://www.atstake.com),    Peter   Grundl   of   KPMG,   Joe   Smith
   (jsm1th@hotmail.com)    and   zenomorph   (admin@cgisecurity.com)   of
   http://www.cgisecurity.com,   Keigo  Yamazaki  of  the  LAC  SNS  Team
   (http://www.lac.co.jp/security/), and Thor Larholm of Jubii A/S.
     _________________________________________________________________

   Author: Shawn V. Hernan
   ______________________________________________________________________

   This document is available from:
   http://www.cert.org/advisories/CA-2002-09.html
   ______________________________________________________________________

CERT/CC Contact Information

   Email: cert@cert.org
          Phone: +1 412-268-7090 (24-hour hotline)
          Fax: +1 412-268-6989
          Postal address:
          CERT Coordination Center
          Software Engineering Institute
          Carnegie Mellon University
          Pittsburgh PA 15213-3890
          U.S.A.

   CERT/CC   personnel   answer  the  hotline  08:00-17:00  EST(GMT-5)  /
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Using encryption

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   If  you  prefer  to  use  DES,  please  call the CERT hotline for more
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Getting security information

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   ______________________________________________________________________

   NO WARRANTY
   Any  material furnished by Carnegie Mellon University and the Software
   Engineering  Institute  is  furnished  on  an  "as is" basis. Carnegie
   Mellon University makes no warranties of any kind, either expressed or
   implied  as  to  any matter including, but not limited to, warranty of
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     _________________________________________________________________

   Conditions for use, disclaimers, and sponsorship information

   Copyright 2002 Carnegie Mellon University.

   Revision History
April 11, 2002:  Initial release

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