A denial-of-service vulnerability exists in the Windows 2000 Telnet service that is caused by the manner in which Telnet handles a logon command that contains a particular deformity. If an attacker entered such a command, it would cause the Telnet service to stop working. The administrator could restore normal service by restarting the Telnet session.

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Mitigating Factors

•	It would not be necessary to reboot the server to recover from this vulnerability. At worst, the Telnet service would need to be restarted.
•	This vulnerability cannot be used to gain additional privileges on the computer; it is a denial-of-service vulnerability only.

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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 English version of this fix should have the following file attributes or later:

   Date        Time    Version      Size     File name
   -----------------------------------------------------
   05/24/2001  04:14p  5.0.33667.1  186,128  Tlntsvr.exe
				

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Microsoft has confirmed that this problem may cause a degree of security vulnerability in Microsoft Windows 2000. This problem was first corrected in Windows 2000 Service Pack 3.

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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: 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: For additional information about what is fixed by this patch, click the article number below to view the article in the Microsoft Knowledge Base: For more information about this vulnerability, see the following Microsoft Web site:

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