MS01-040: Invalid RDP Data Can Cause Memory Leak in Terminal Services (292435)


The information in this article applies to:

  • Microsoft Windows NT Server 4.0 Terminal Server Edition SP4
  • Microsoft Windows NT Server 4.0 Terminal Server Edition SP5
  • Microsoft Windows NT Server 4.0 Terminal Server Edition SP6
  • Microsoft Windows 2000 Server SP1
  • Microsoft Windows 2000 Server SP2
  • Microsoft Windows 2000 Advanced Server SP1
  • Microsoft Windows 2000 Advanced Server SP2
This article was previously published under Q292435

SYMPTOMS

The Windows 2000 Terminal Services component and Windows NT Server 4.0, Terminal Server Edition, contain a memory leak in one of the functions that processes incoming Remote Data Protocol (RDP) data via port 3389. Each time that an RDP packet that contains a specific type of malformation is processed, the memory leak depletes overall server memory by a small amount.

If an attacker were to send a sufficiently large quantity of such data to an affected computer, the attacker could deplete the computer's memory to the point where the response time would be slowed or the computer's ability to respond would be stopped altogether. All system services would be affected including but not limited to Terminal Services. Normal operation could be restored by restarting the computer.

RESOLUTION

Windows 2000

To resolve this problem, obtain either the hotfix that is 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 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 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

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:

DownloadDownload Q292435_W2K_SP3_x86_en.exe now

Release Date: July 24, 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 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
   ----------------------------------------------------
   6/27/2001  10:10a  5.0.2195.3356  19,928  Tdipx.sys
   6/27/2001  10:10a  5.0.2195.3356  17,496  Tdnetb.sys
   6/27/2001  10:10a  5.0.2195.3356  18,168  Tdtcp.sys

Windows NT Server 4.0, Terminal Server Edition

To resolve this problem, either obtain the hotfix referenced in this section or the Windows NT Server 4.0, Terminal Server Edition, Security Rollup Package (SRP). For additional information about the SRP, click the article number below to view the article in the Microsoft Knowledge Base:

317636 Windows NT Server 4.0, Terminal Server Edition, Security Rollup Package

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that you determine are at risk of attack. Evaluate the computer's physical accessibility, network and Internet connectivity, and other factors to determine the degree of risk to the computer. See the associated Microsoft Security Bulletin to help determine the degree of risk. This hotfix may receive additional testing. If the computer is sufficiently at risk, we recommend that you apply this hotfix now.

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

http://support.microsoft.com/contactus/?ws=support

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:

DownloadDownload Q292435i.exe now

Release Date: July 24, 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 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
   ------------------------------------------------------
   13-Jun-2001  17:47  4.0.1381.33478  18,520  Tdipx.sys
   13-Jun-2001  17:47  4.0.1381.33478  17,048  Tdnetb.sys
   13-Jun-2001  17:47  4.0.1381.33478  18,392  Tdtcp.sys

STATUS

Windows 2000

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Windows 2000.

Windows NT Server 4.0, Terminal Server Edition

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Windows NT Server 4.0, Terminal Server Edition.

MORE INFORMATION

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

http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS01-040.asp

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

Modification Type:MajorLast Reviewed:10/8/2006
Keywords:kbHotfixServer kbQFE kbbug kbfix kbnetwork kbSecurity KbSECVulnerability kbTermServ kbWin2000PreSP3Fix kbWin2000sp3fix KB292435
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