MS00-077: Denial of Service Can Occur with Microsoft NetMeeting

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View products that this article applies to.

This article was previously published under Q273854

SYMPTOMS

A port attack on port 1720, which is used by the NetMeeting Remote Desktop Sharing (RDS) process (Mnmsvc.exe), may cause excessive CPU usage.

When this occurs, single-processor computers may experience 100 percent CPU usage; dual-processor computers experience 50 percent CPU usage, and so on.

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CAUSE

RDS does not properly handle a returned value from Winsock.

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RESOLUTION

NetMeeting for Windows 2000

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

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that you determine are at risk of attack. Evaluate your computer's physical accessibility, network and Internet connectivity, and other factors to determine the degree of risk to your computer. See the associated Microsoft Security Bulletin (http://www.microsoft.com/technet/security/bulletin/MS00-077.mspx) to help determine the degree of risk. This fix may receive additional testing. If your computer is sufficiently at risk, Microsoft recommends that you apply this fix now. Otherwise, wait for the next Windows 2000 service pack that contains this fix.

To resolve this problem immediately, download the fix by following the instructions later in this article or contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS (http://support.microsoft.com/default.aspx?scid=fh;en-us;cntactms)

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

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

Collapse this imageExpand this image

Download Q299796_W2k_SP3_x86_en.exe now (http://www.microsoft.com/Downloads/Release.asp?ReleaseID=30963)

Release Date: June 20, 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
   --------------------------------------------------
   5/24/2001  1:45p  4.4.0.3385  384 KB  Callcont.dll

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NetMeeting for Windows NT 4.0

To resolve this problem for NetMeeting for Windows 95, Windows 98, Windows Me, and Windows NT 4.0, obtain NetMeeting Service Pack 2 (SP2) from the following Microsoft web site:

http://www.microsoft.com/windows/netmeeting/download/nm301x86.asp (http://www.microsoft.com/windows/netmeeting/download/nm301x86.asp)

NOTE: SP2 is not available for NetMeeting for Windows 2000 has not been made available for Windows 2000.

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STATUS

NetMeeting for Windows 2000

Microsoft has confirmed that this is a problem in NetMeeting 3.01 for Windows 2000.

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NetMeeting for Windows NT 4.0

Microsoft has confirmed that this is a problem in NetMeeting 3.01 for Windows NT 4.0.

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MORE INFORMATION

For related information about this problem, please visit the following Microsoft Web site:

http://www.microsoft.com/technet/security/bulletin/ms00-077.mspx (http://www.microsoft.com/technet/security/bulletin/ms00-077.mspx)

For additional security-related information about Microsoft products, please visit the following Microsoft Web site:

http://www.microsoft.com/security/ (http://www.microsoft.com/security/)

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APPLIES TO

Microsoft NetMeeting 3.01 Standard Edition

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kbbug kbenv kbfix kbsecurity kbsecvulnerability kbwin2000presp3fix KB273854

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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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