Article ID: 269049
Article Last Modified on 3/29/2007
APPLIES TO
- Microsoft Windows NT Server 4.0, Terminal Server Edition
- Microsoft Windows 2000 Server
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows 2000 Professional Edition
- Microsoft Windows NT Server 4.0 Standard Edition
- Microsoft Windows NT Server 4.0 Enterprise Edition
- Microsoft Windows NT Workstation 4.0 Developer Edition
This article was previously published under Q269049
SYMPTOMS
It may be possible for a malicious user to place a program named Explorer.exe in the C:\ folder (the root of drive C) so that it is run in place of the standard Windows shell program. By default, the share permissions on the C:\ folder are set to Everyone Full Access. Anyone who has access to this share, either locally or through a network connection, can place a program there that is run before the Explorer.exe shell.
CAUSE
This issue can occur when you start a program by using a registry key if the entry does not specify an absolute path. Without a complete path, a standard path search order is followed. For example, the Shell value in the HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon key has a default value of "Explorer.exe" without any path information. During startup, when this value is read (without an explicit path), Windows attempts to locate the program by using a folder search. Contrary to the Windows 2000 documentation, the C:\ folder is the first location that is checked. Any program located there that is named Explorer.exe is run in place of the correct shell program.
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 following files are available for download from the Microsoft Download Center:
![[GRAPHIC: Download]](/wiki/index.php?title=File:Download.gif){kind=small}
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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 Size File name
---------------------------------------
07/18/00 05:07p 331,536 Msgina.dll
07/18/00 05:07p 17,680 Userinit.exe
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:
299444 Post-Windows NT 4.0 Service Pack 6a Security Rollup Package (SRP)
The following files are available for download from the Microsoft Download Center:
Intel:
Alpha:
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 Size File name Platform
-----------------------------------------------
07/18/00 07:27p 124,176 Msgina.dll Intel
07/18/00 07:25p 160,528 Msgina.dll Alpha
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 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:
Intel:
Alpha:
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 Size File name Platform
-----------------------------------------------
07/18/00 07:22p 207,120 Msgina.dll Intel
07/18/00 07:08p 259,344 Msgina.dll Alpha
STATUS
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 2.
Windows NT 4.0
Microsoft has confirmed that this problem may cause a degree of security vulnerability in Microsoft Windows NT 4.0.
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 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:
For additional information about how to install Windows 2000 and Windows 2000 hotfixes at the same time, click the article number below to view the article in the Microsoft Knowledge Base:
249149 Installing Microsoft Windows 2000 and Windows 2000 Hotfixes
Additional query words: security_patch kbtsesrp
Keywords: kbhotfixserver kbqfe kbbug kbdocerr kbfix kbgraphxlinkcritical kbsecbulletin kbsecurity kbsecvulnerability kbwin2000presp2fix KB269049
