After you install the TCP/IP Printing service on a Windows NT 4.0-based computer or the Print Services for UNIX component on a Windows 2000-based computer, it may be possible to exploit a security vulnerability in the Line Printer Daemon (LPD) Server service on those computers. By sending a specially-malformed print request via the LPD Server service, a malicious user could cause the service to stop, preventing the computer from servicing some print requests. Other services may also be affected by stopping this service, including the Dynamic Host Control Protocol (DHCP) service. Affected services can be put back in service by restarting them; it is not necessary to reboot the computer.

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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: The following files are available for download from the Microsoft Download Center:

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Windows NT 4.0

To resolve this problem, obtain the individual package referenced below or obtain the Windows NT 4.0 Security Rollup Package. For additional information on the SRP, click the article number below to view the article in the Microsoft Knowledge Base: The following files are available for download from the Microsoft Download Center:
For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base: 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   Platform
   ---------------------------------------------------------------
   03/28/2000  07:43p  4.0.1381.7046  23,312  Lpdsvc.dll  Intel
   03/28/2000  07:42p  4.0.1381.7046  38,160  Lpdsvc.dll  Alpha
				

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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: 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 are experiencing this specific problem.

To resolve this problem, 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: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 files are available for download from the Microsoft Download Center:
For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base: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 secure servers that 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   Platform
   ---------------------------------------------------------------
   03/24/2000  04:39p  4.0.1381.33397  23,312 Lpdsvc.dll  Intel
				

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Windows 2000

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Windows 2000. This problem was first corrected in Windows 2000 Service Pack 1.

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Windows NT 4.0

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

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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.

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The Line Printer Daemon Server service is a feature of the TCP/IP Printing service for Windows NT 4.0 and the Print Services for UNIX component for Windows 2000. Both services provide for integration into UNIX environments. These services are based on the Berkeley Remote Printing protocols commonly called Line Printer Daemon (LPD) and Line Printer Remote (LPR). These are described in RFC 1179.

The native Windows NT and Windows 2000 printing services are not affected by this vulnerability. Although the native Windows NT and Windows 2000 printing services do operate in a TCP/IP environment, they operate with different protocols.

NOTE: The TCP/IP Printing service and Print Services for UNIX are not the same thing as the native Windows NT and Windows 2000 printing services (Spoolss). The TCP/IP Printing service and Print Services for UNIX are not installed by default; this vulnerability does not allow a malicious user to disrupt printing via the native Windows NT 4.0 and Windows 2000 printing services.

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

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