IIS: Malformed URL Can Cause Service Failure in IIS 5.0 and Exchange 2000 Server

Article translations Article translations
Article ID: 286818 - View products that this article applies to.
This article was previously published under Q286818
This article has been archived. It is offered "as is" and will no longer be updated.
Expand all | Collapse all

SYMPTOMS

Microsoft Internet Information Services (IIS) 5.0 contains a flaw that affects the way that a URL is handled if it has a specific construction and its length is within a very narrow range of values. If such a URL were repeatedly sent to an affected system, a confluence of events could cause a memory allocation error that would result in the failure of the IIS service.

IIS 5.0 is affected by the same vulnerability as the Microsoft Exchange 2000 Server vulnerability that is described in the following article in the Microsoft Knowledge Base:
287678 XWEB: Malformed URL Can Cause Service Failure in IIS 5.0 and Exchange 2000 Server
Mitigating factors:
  • The vulnerability would not enable the attacker to gain any administrative control over the server or to alter any data on it.
  • The affected services automatically restart in the event of a failure; therefore, an affected system would resume service almost immediately.
  • A successful attack against an Exchange server would only disrupt Web-based mail clients' use of the server. The server would continue to be available for MAPI-based clients such as Microsoft Outlook.
  • The ISAPI involved in this vulnerability authenticates the user before servicing the request; therefore, a properly configured Exchange server would be at less risk than an IIS server.

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 How to Obtain the Latest Windows 2000 Service Pack
IMPORTANT: Because the flaw occurs in two different code modules, one of which is installed as part of IIS 5.0 and both of which are installed as part of Exchange 2000, it is important for Exchange 2000 administrators to install both the IIS and Exchange patches below.

The following files are available for download from the Microsoft Download Center:
IIS 5.0:
Collapse this imageExpand this image
Download
English Language Version

Collapse this imageExpand this image
Download
Arabic Language Version

Collapse this imageExpand this image
Download
Chinese (Simplified) Language Version

Collapse this imageExpand this image
Download
Chinese (Traditional) Language Version

Collapse this imageExpand this image
Download
Czech Language Version

Collapse this imageExpand this image
Download
Danish Language Version

Collapse this imageExpand this image
Download
Dutch Language Version

Collapse this imageExpand this image
Download
Finnish Language Version

Collapse this imageExpand this image
Download
French Language Version

Collapse this imageExpand this image
Download
German Language Version

Collapse this imageExpand this image
Download
Greek Language Version

Collapse this imageExpand this image
Download
Hebrew Language Version

Collapse this imageExpand this image
Download
Hungarian Language Version

Collapse this imageExpand this image
Download
Italian Language Version

Collapse this imageExpand this image
Download
Japanese Language Version

Collapse this imageExpand this image
Download
Japanese NEC Language Version

Collapse this imageExpand this image
Download
Korean Language Version

Collapse this imageExpand this image
Download
Norwegian Language Version

Collapse this imageExpand this image
Download
Polish Language Version

Collapse this imageExpand this image
Download
Portuguese (Brazilian) Language Version

Collapse this imageExpand this image
Download
Portuguese Language Version

Collapse this imageExpand this image
Download
Russian Language Version

Collapse this imageExpand this image
Download
Spanish Language Version

Collapse this imageExpand this image
Download
Swedish Language Version

Collapse this imageExpand this image
Download
Turkish Language Version

Exchange 2000 Server:
Collapse this imageExpand this image
Download
Download Q287678engi386.exe now
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
   -----------------------------------------------------
   02/01/2001  07:21p  0.9.3940.16  428,816  Httpext.dll
				

STATUS

Microsoft has confirmed that this is a problem in Microsoft Internet Information Services 5.0. This problem was first corrected in Windows 2000 Service Pack 2.

MORE INFORMATION

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 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 Use QChain.exe to Install Multiple Hotfixes with One Reboot
For more information about this issue, see the following Microsoft Web site:
http://www.microsoft.com/technet/security/bulletin/ms01-014.mspx
For additional information about how to install Microsoft Windows 2000 and Microsoft Windows 2000 hotfixes at the same time, click the article number below to view the article in the Microsoft Knowledge Base:
249149 Installing Microsoft Windows 2000 and Windows 2000 Hotfixes

Properties

Article ID: 286818 - Last Review: October 23, 2013 - Revision: 3.1
APPLIES TO
  • Microsoft Internet Information Services 5.0
Keywords: 
kbnosurvey kbarchive kbhotfixserver kbqfe kbbug kbfix kbgraphxlinkcritical kbwin2000presp2fix KB286818

Contact us for more help

Contact us for more help
Connect with Answer Desk for expert help.
Get more support from smallbusiness.support.microsoft.com