MS01-044: Patch Available for MIME Header Denial of Service Vulnerability

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View products that this article applies to.

This article was previously published under Q304867

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SYMPTOMS

A denial of service vulnerability exists in Internet Information Services (IIS) 5.0 because of the way IIS interprets content that contains a particular type of invalid MIME header. If an attacker places content that contains this type of defect onto a server, and then requests it, the IIS service is unable to serve any content until a spurious entry is removed from the File Type table for the site.

In order to exploit this vulnerability, the attacker must have the ability to place content onto an affected Web server. However, best practices strongly recommend that you never allow an untrusted user to install content on a Web server. The vulnerability affects only IIS 5.0 servers, and does not allow an attacker to gain any privileges on the server.

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CAUSE

This vulnerability occurs because of the way IIS handles MIME information when serving content. If the MIME content-type information is malformed in a particular way, the service fails when trying to process it.

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RESOLUTION

To resolve this problem, either obtain the hotfix referenced in this section or Windows 2000 Security Rollup Package 1 (SRP1). For additional information about SRP1, click the article number below to view the article in the Microsoft Knowledge Base:

311401 (http://support.microsoft.com/kb/311401/EN-US/ ) Windows 2000 Security Rollup Package 1 (SRP1), January 2002

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 (http://support.microsoft.com/kb/260910/EN-US/ ) How to Obtain the Latest Windows 2000 Service Pack

The following file is available for download from the Microsoft Download Center:

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Download Q301625_W2K_SP3_x86_en.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=32011)

NOTE: This patch can be installed on systems running Windows 2000 Service Pack 1 or Windows 2000 Service Pack 2. You must reapply the security rollup patch after you install a Windows 2000 Service Pack.

Release Date: August 15, 2001

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 (http://support.microsoft.com/kb/119591/EN-US/ ) 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
   -------------------------------------------------------
   30-Jul-2001  17:46  5.0.2195.3785  246,032  Httpext.dll

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STATUS

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Internet Information Services 5.0. This problem was first corrected in Windows 2000 Service Pack 3.

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MORE INFORMATION

This patch also contains fixes for the problems described in the following Microsoft Knowledge Base article:

297860 (http://support.microsoft.com/kb/297860/EN-US/ ) IIS 5.0 Security and Post-Windows NT 4.0 SP5 IIS 4.0 Patch Rollup

For more information on this vulnerability, see the following Microsoft Web site:

http://www.microsoft.com/technet/security/bulletin/ms01-044.mspx (http://www.microsoft.com/technet/security/bulletin/ms01-044.mspx)

For additional information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the article number below to view the article in the Microsoft Knowledge Base:

265173 (http://support.microsoft.com/kb/265173/EN-US/ ) The Datacenter Program and Windows 2000 Datacenter Server Product

For additional information about how to install multiple hotfixes with only one reboot, click the article number below to view the article in the Microsoft Knowledge Base:

296861 (http://support.microsoft.com/kb/296861/EN-US/ ) Use QChain.exe to Install Multiple Hotfixes with One Reboot

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APPLIES TO

Microsoft Internet Information Services 5.0

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kbhotfixserver kbqfe kbbug kbfix kbsecdos kbsechack kbsecurity kbsecvulnerability kbwin2000presp3fix kbwin2000sp3fix KB304867

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Retired KB Content Disclaimer

This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.

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