DOCUMENT:Q277873 08-MAY-2002 [iis] TITLE :Patch for "Web Server File Request Parsing" Vulnerability PRODUCT :Internet Information Server PROD/VER::4.0,5.0 OPER/SYS: KEYWORDS:kbSecurity kbWinNT400PreSP7Fix kbWin2000PreSP2Fix kbWin2000SP2Fix kbgraphxlinkcritical ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Internet Information Services version 5.0 - Microsoft Internet Information Server version 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== Microsoft has released a patch that eliminates a serious security vulnerability in Microsoft Internet Information Services (IIS) 5.0 or Internet Information Server 4.0. When IIS receives a valid request for an executable file, it passes the name of the requested file to the underlying operating system for processing. However, because of an implementation flaw, it is possible to create a specially malformed file request that contains both a file name and one or more operating system commands. When it receives such a request, IIS passes the entire string to the operating system, which first processes the file, and then executes the commands. The file must reside in a folder to which the user has execute permissions, but it does not necessarily need to be an executable file. The ability to execute operating system commands on a Web server can enable a malicious user to take virtually any action that an interactively logged on user can take. Although this does not give the malicious user administrative control over the server, it can nevertheless allow him to cause widespread damage. He could, for instance, add, delete or change files on the server, run code that was already on the server, or upload and run the code of his choice. For more information on this vulnerability, see the following Microsoft Web site: http://www.microsoft.com/technet/security/bulletin/ms00-086.asp RESOLUTION ========== Windows 2000 ------------ To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, please see the following article in the Microsoft Knowledge Base: Q260910 How to Obtain the Latest Windows 2000 Service Pack The following files are available for download from the Microsoft Download Center: US English: DownloadDownload Q277873_W2K_SP2_x86_en.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=25547) Chinese (Simplified): DownloadDownload Q277873_W2K_SP2_x86_cn.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=25580) Chinese (Traditional): DownloadDownload Q277873_W2K_SP2_x86_tw.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=25581) For additional information about how to download Microsoft Support files, click the article number below to view the article in the Microsoft Knowledge Base: Q119591 How to Obtain Microsoft Support Files from Online Services Microsoft used the most current virus detection software available on the date of posting to scan this file for viruses. After it is posted, the file is housed on secure servers that prevent any unauthorized changes to the file. The English version of this fix should have the following file attributes or later: Date Time Version Size File name ------------------------------------------------------ 11/27/2000 10:12p 5.0.2195.2785 122,640 Iisrtl.dll 11/27/2000 10:12p 5.0.2195.2784 357,136 W3svc.dll Windows NT 4.0 -------------- A supported fix is now available from Microsoft, but it is only intended to correct the problem described in this article and should be applied only to systems experiencing this specific problem. To resolve this problem, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web: http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS NOTE: In special cases, charges that are normally incurred for support calls may be canceled, if a Microsoft Support Professional determines that a specific update will resolve your problem. Normal support costs will apply to additional support questions and issues that do not qualify for the specific update in question. The following files are available for download from the Microsoft Download Center: NOTE: It is important that you have installed the latest service pack before you apply this patch. US English: DownloadDownload Arbexei.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=25964) Chinese (Simplified): DownloadDownload Arbexei.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=25966) Chinese (Traditional): DownloadDownload Arbexei.exe now (http://www.microsoft.com/downloads/release.asp?ReleaseID=25965) For additional information about how to download Microsoft Support files, click the article number below to view the article in the Microsoft Knowledge Base: Q119591 How to Obtain Microsoft Support Files from Online Services Microsoft used the most current virus detection software available on the date of posting to scan this file for viruses. After it is posted, the file is housed on secure servers that prevent any unauthorized changes to the file. The English version of this fix should have the following file attributes or later: Date Time Version Size File name ---------------------------------------------------- 11/08/2000 03:29p 4.2.753.1 214,544 adsiis.dll 11/09/2000 05:32p 4.2.753.1 330,672 asp.dll 11/08/2000 02:39p 11,396 httpext.h 11/09/2000 05:38p 4.2.753.1 55,904 httpodbc.dll 11/08/2000 03:29p 4.2.753.1 98,912 iischema.dll 11/08/2000 02:39p 28,851 iiscnfg.h 11/08/2000 03:27p 4.2.753.1 185,792 infocomm.dll 11/09/2000 05:38p 4.2.753.1 38,256 ssinc.dll 11/08/2000 03:28p 4.2.753.1 25,360 sspifilt.dll 11/09/2000 05:37p 4.2.753.1 229,008 w3svc.dll NOTE: Due to file dependencies, this hotfix requires Microsoft Windows NT 4.0 Service Pack 5 or Service Pack 6a. Microsoft Windows NT Server version 4.0, Terminal Server Edition ---------------------------------------------------------------- To resolve this problem, obtain the Windows NT Server 4.0, Terminal Server Edition, Security Rollup Package (SRP). For additional information about the SRP, click the article number below to view the article in the Microsoft Knowledge Base: Q317636 Windows NT Server 4.0, Terminal Server Edition, Security Rollup Package STATUS ====== Windows 2000 ------------ Microsoft has confirmed this to be a problem in Internet Information Services 5.0. This problem was first corrected in Windows 2000 Service Pack 2. Windows NT 4.0 -------------- Microsoft has confirmed this to be a problem in Internet Information Server 4.0. Additional query words: security_patch ====================================================================== Keywords : kbSecurity kbWinNT400PreSP7Fix kbWin2000PreSP2Fix kbWin2000SP2Fix kbgraphxlinkcritical Technology : kbiisSearch kbiis500 kbiis400 Version : :4.0,5.0 Hardware : x86 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.