MS01-044: Patch Available for WebDAV Denial of Service

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View products that this article applies to.

This article was previously published under Q298340

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SYMPTOMS

In Internet Information Services (IIS) 5.0, a denial of service vulnerability exists that an attacker could exploit to temporarily disrupt Web services on an IIS 5.0 server.

Mitigating Factors:

The effect of an attack would be temporary. The server would automatically resume normal service as soon as the malformed requests stopped arriving.
This vulnerability does not provide an attacker with any capability to carry out WebDAV requests.
This vulnerability does not provide any capability to compromise data on the server or gain administrative control over it.
This vulnerability only affects IIS 5.0.

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This vulnerability occurs because of the way that WebDAV handles a particular type of very long, invalid request. The net effect is to cause an access violation that results in the failure of the IIS 5.0 process.

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RESOLUTION

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 English version of this fix should have the following file attributes or later:

   Date         Time  Version        Size     File name
   ------------------------------------------------------
   12-May-2001  1815  5.0.2195.3608  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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kbbug kbfix kbsecbulletin kbsechack kbsecurity kbsecvulnerability kbwin2000presp3fix kbwin2000sp3fix KB298340

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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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