Security Bulletin

Microsoft Security Bulletin MS98-019 - Important

Patch Available for IIS 'GET' Vulnerability

Published: December 21, 1998 | Updated: March 10, 2003

Version: 2.0

Patch Availability Information Updated: March 10, 2003

Originally Posted: December 21, 1998

Summary

Microsoft has released a patch that fixes a vulnerability in Microsoft® Internet Information Server® that could allow denial-of-service attacks to be mounted against web servers.

There have been no reports of customers being affected by this vulnerability. However, Microsoft is publishing this bulletin and releasing the patch to allow customers to address the potential security risk it poses. As detailed below in What Customers Should Do, Microsoft recommends that users evaluate whether they are at risk from this attack and install the patch if appropriate.

Issue

This vulnerability involves the HTTP GET method, which is used to obtain information from an IIS web server. Specially-malformed GET requests can create a denial of service situation that consumes all server resources, causing a server to "hang." In some cases, the server can be put back into service by stopping and restarting IIS; in others, the server may need to be rebooted. This situation cannot happen accidentally. The malformed GET requests must be deliberately constructed and sent to the server. It is important to note that this vulnerability does not allow data on the server to be compromised, nor does it allow any privileges on it to be usurped.

Affected Software Versions

  • Microsoft Internet Information Server, versions 3.0 and 4.0, on x86 and Alpha platforms.

Vulnerability Identifier: CVE-1999-1035

What Microsoft is Doing

On December 21, Microsoft released a patch that fixes the problem identified. This patch is available for download from the sites listed below. Please see What Customers Should Do for additional information on the patch.

Microsoft has sent this security bulletin to customers subscribing to the Microsoft Product Security Notification Service. See The Microsoft Product Security Notification Service for more information about this free customer service.

Microsoft has published the following Knowledge Base (KB) article on this issue:

  • Microsoft Knowledge Base (KB) article 192296, IIS: Patch Available for IIS "GET" Vulnerability, https: .

    (Note It might take 24 hours from the original posting of this bulletin for the updated KB article to be visible in the Web-based Knowledge Base.)

Microsoft has released the following hot fixes:

  • Fix for IIS 3.0 on X86 platforms:

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  • Fix for IIS 4.0 on X86 platforms:

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  • Fix for IIS 3.0 on Alpha platforms:

    </https:>https:

  • Fix for IIS 4.0 on Alpha platforms:

    </https:>https:

What Customers Should Do

The patch for this vulnerability is fully supported. However, it has not been fully regression tested and should only be applied to systems determined to be at risk of attack. A fully regression-tested version of the patch will be available as part of the next Windows NT service pack.

Microsoft recommends that customers evaluate the degree of risk that this vulnerability poses to their systems, based on physical accessibility, network and Internet connectivity, and other factors, and determine whether the appropriate course of action is to apply the patch or wait for the next service pack.

More Information

Please see the following references for more information related to this issue.

  • Microsoft Security Bulletin 98-019, Patch Available for IIS "GET" Vulnerability (the Web-posted version of this bulletin), https://www.microsoft.com/technet/security/bulletin/ms98-019.mspx.

  • Microsoft Knowledge Base (KB) article 192296, IIS: Patch Available for IIS "GET" Vulnerability, </https:>https:.

    (Note   It might take 24 hours from the original posting of this bulletin for the updated KB article to be visible in the Web-based Knowledge Base.)

Obtaining Support on this Issue

This is a supported patch. If you have problems installing this patch or require technical assistance with this patch, please contact Microsoft Technical Support. For information on contacting Microsoft Technical Support, please see </https:>https:.

Acknowledgments

Microsoft wishes to acknowledge the contribution made by Eugene Kalinin of the N. N.Burdenko Neurosurgery Institute and Brian Steele of Cable and Wireless Grenada, Ltd. (https://www.candw.gd), who reported the problem to us.

Revisions

  • December 21, 1998: Bulletin Created
  • V2.0 (March 10, 2003): Introduced versioning and updated patch availability information

For additional security-related information about Microsoft products, please visit https://www.microsoft.com/technet/security

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