SYMPTOMS
A denial of service vulnerability exists in Terminal Services in Windows 2000 and in Windows NT Server 4.0, Terminal Server Edition. An attacker may use this vulnerability to cause a Windows 2000 or a Windows NT 4.0 terminal server to fail. The server may be restarted without incident, but any work that was in progress at the time of the failure will be lost.
Mitigating factors
- There is no capability to breach the security of a terminal server session by using this vulnerability, or to add, change, or delete data on the server. It is a denial of service vulnerability only.
- The specific sequence of data packets that are involved in this vulnerability cannot be generated as part of a legitimate terminal server session.
Important When you try to connect to RDP-TCP sessions after you apply the October 18, 2001 version of the Windows 2000 update, you may receive the following error message:
Terminal service client disconnected
The client did not connect to the terminal server. The server may be too busy. Please try connecting later.
To resolve this problem, apply the October 22, 2001 version of the Windows 2000 update. See the "Resolution" section for information about how to obtain the latest update.
This problem does not occur with the Windows NT Server 4.0, Terminal Services Edition update.
RESOLUTION
Windows 2000
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
The resolution for this problem is also included in Windows 2000 Security Rollup Package 1 (SRP1).
For additional information about SRP1, click the following article number to view the article in the Microsoft Knowledge Base:
311401
Windows 2000 Security Rollup Package 1 (SR about SRP1), January 2002
The following file is available for download from the Microsoft Download Center:
Release Date: October 22, 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 hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the
Time Zone tab in the Date and Time tool in Control Panel.
Date Time Version Size File name
--------------------------------------------------------------------
19-Oct-2001 14:40 5.0.2195.3895 125,712 Icaapi.dll
19-Oct-2001 14:42 5.0.2195.4527 107,280 Instrdp5.dll
19-Jul-2001 20:39 5.0.2195.3895 93,456 Licmgr.exe
28-Sep-2001 18:30 5.0.2195.4435 330,000 Lserver.exe
19-Oct-2001 14:40 5.0.2195.3895 26,384 Mstlsapi.dll
19-Oct-2001 14:42 5.0.2195.4527 89,080 Rdpwd.sys 128-bit
19-Oct-2001 14:42 5.0.2195.4527 89,048 Rdpwd.sys 56-bit
18-Oct-2001 21:22 5.0.2195.4527 100,248 Rdpwsx.dll
19-Jul-2001 20:39 5.0.2195.3895 141,584 Termsrv.exe
19-Oct-2001 14:40 5.0.2195.3895 23,312 Tls236.dll
Note Because of file dependencies, this update requires Windows 2000 Service Pack 1 or Service Pack 2.
Windows NT Server 4.0, Terminal Server Edition
The following file is available for download from the Microsoft Download Center:
Download the WindowsNT4TerminalServer-KB307454-x86-ENU.EXE package now.
Release Date: May 11, 2004
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 hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the
Time Zone tab in the Date and Time tool in Control Panel.
Date Time Version Size File name
--------------------------------------------------------------
14-Apr-2004 10:08 4.0.1381.33564 70,928 Icaapi.dll
14-Apr-2004 10:10 4.0.1381.33564 91,608 Rdpwd.sys
15-Feb-2002 21:27 4.0.1381.33528 41,880 Rdpwsx.dll
The English version of the original security update (Q307454i.exe) was released on October 19, 2001. The original update has the file attributes that are listed in the following table.
Date Time Version Size File name
---------------------------------------------------------
31-Jul-2001 11:22 4.0.1381.33478 61,712 Icaapi.dll
08-Oct-2001 16:16 4.0.1381.33478 91,512 Rdpwd.sys
08-Oct-2001 16:36 4.0.1381.33478 41,880 Rdpwsx.dll
Note Because of file dependencies, this update requires Windows NT Server 4.0, Terminal Server Edition Service Pack 6.