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:
RESOLUTION
Windows 2000
To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the
Microsoft Knowledge Base:
260910 How to Obtain the Latest Windows 2000 Service Pack
The following files are available for download from the Microsoft
Download Center:
For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591 How to Obtain Microsoft Support Files from Online Services
Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to 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 that is described in this article. Apply it only to computers that are 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 about support costs, visit the following Microsoft Web site:
NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual 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.
For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:
119591 How to Obtain Microsoft Support Files from Online Services
Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to 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:
317636 Windows NT Server 4.0, Terminal
Server Edition, Security Rollup Package
