Knowledge Base

MS02-004: Telnet Server Is Vulnerable to a Denial-of-Service Attack

Article ID: 307298

Article Last Modified on 1/31/2007

APPLIES TO

Microsoft Windows 2000 Service Pack 1
Microsoft Windows 2000 Service Pack 2
Microsoft Windows 2000 Advanced Server
Microsoft Windows 2000 Advanced Server
Microsoft Windows 2000 Service Pack 1
Microsoft Windows 2000 Service Pack 2
Microsoft Interix 2.2 Standard Edition
Microsoft Interix 2.2 Standard Edition
Microsoft Interix 2.2 Standard Edition
Microsoft Interix 2.2 Standard Edition
Microsoft Interix 2.2 Standard Edition
Microsoft Interix 2.2 Standard Edition
Microsoft Interix 2.2 Standard Edition

This article was previously published under Q307298

SYMPTOMS

There is a buffer-overflow vulnerability that affects two Microsoft products: the Telnet service in Windows 2000 and the Telnet daemon (telnetd) in Microsoft Interix 2.2. By sending a specially malformed request to the Telnet server, an attacker could cause either of two results. In the simpler case, this could cause the Telnet server to stop working. In the more complex case, this could allow an attacker to run code of his or her choice on the server.

Microsoft strongly recommends that you use Telnet on only fully trusted networks. You should not use Telnet across the Internet; you should block Telnet connections at your corporate firewall. Neither Windows 2000 nor Interix is affected by by this vulnerability under default conditions.

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 the hotfix in this article and in 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

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

Release Date: February 7, 2002

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
   -----------------------------------------------------
   24-Sep-2001  14:40  5.0.33668.1  186,128  Tlntsvr.exe

Internix 2.2

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:

Download In.telnetd now

Release Date: February 7, 2002

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 secure servers that prevent any unauthorized changes to the file.

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

   Version    Size     File name
   ------------------------------
   2.2.428.1  170,856  In.telnetd

STATUS

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Windows 2000 and Interix 2.2. This problem was first corrected in Windows 2000 Service Pack 3.

MORE INFORMATION

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

http://www.microsoft.com/technet/security/bulletin/MS02-004.mspx

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

Additional query words: DOS kbWin2000srp1 security_patch

Keywords: kbbug kbfix kbwin2000presp3fix kbsecvulnerability kbqfe kbwin2000sp3fix kbsecurity kbsecdos kbsecbulletin kbsechack kbhotfixserver KB307298

Microsoft KB Archive/307298

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