This article was previously published under Q277873
This article has been archived. It is offered "as is" and will no longer be updated.
We strongly recommend that all users upgrade to Microsoft Internet Information Services (IIS) version 7.0 running on Microsoft Windows Server 2008. IIS 7.0 significantly increases Web infrastructure security. For more information about IIS security-related topics, visit the following Microsoft Web site:
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:
For more 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 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
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 more information about the SRP, click the following article number to view the article in the Microsoft Knowledge Base:
317636 Windows NT Server 4.0, Terminal Server Edition, Security Rollup Package
Microsoft has confirmed that this is 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 that this is a problem in Internet Information Server 4.0.
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates