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Q239105: Jet 3.5 Text ISAM Allows User to Append Lines to System File

Article: Q239105
Product(s): Open Database Connectivity (ODBC)
Version(s): WINDOWS:3.5,97
Operating System(s): 
Keyword(s): kbdta
Last Modified: 23-NOV-2000

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The information in this article applies to:

- Microsoft Access 97 
- Microsoft Office 97 Professional Edition for Windows 
- Microsoft ODBC Driver for Access, version 3.5 
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Novice: Requires knowledge of the user interface on single-user computers.

SYMPTOMS
========

The Text ISAM allows you to manipulate text files without checking the file name
extension. This creates a potential security risk because it can be used to read
or write to a system text file.

NOTE: Until you add the nonstandard text file extension to the
HKEY_LOCAL_MACHINE\Software\Microsoft\Jet\3.5\Engines\Text\DisabledExtensions
registry key, the error that you will receive during export/import operations
using the updated text ISAM will be:

  Can't Update. Database or object is read-only.

  An error occurred trying to import file.
  '<FullPath and Filename>'. The file was not imported.

CAUSE
=====

The Text ISAM is able to modify the contents of text files that are formatted as
data tables. This feature makes it easy for you to exchange data on different
systems.

RESOLUTION
==========

Install the latest update to the Microsoft Jet database engine. The following
registry key is dynamically added when a program loads the Text ISAM. This
registry key prevents this type of security risk.

  HKEY_LOCAL_MACHINE\Software\Microsoft\Jet\3.5\Engines\Text\DisabledExtensions

For additional information about how to obtain the Microsoft Jet 3.51 update,
please click the article number below to view the article in the Microsoft
Knowledge Base:

  Q172733 ACC97: Updated Version of Microsoft Jet 3.5 Available on MSL

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article.

MORE INFORMATION
================

NOTE: Jet35sp3.exe was updated on October 11, 1999. If you previously installed
this update and would like to use the stricter security control provided in the
updated MSText35.dll run the installed MSText35.REG file. To run the
Mstext35.reg file, locate the file on your system and double-click it.

There could be a possible security risk when someone uses the Text ISAM to modify
any of the system text files, such as Autoexec.bat, Config.sys, System.ini, and
so on.

After you install the updated version of Jet, you will only be able to use the
Text ISAM to update text files with the following extensions:

- txt
- csv
- tab
- asc
- htm
- html

These are the default extensions that are added to the registry key listed in the
"Resolution" section. The Value data for the registry key is:

  !txt,csv,tab,asc,htm,html

In the first release of Jet 3.5 SP3, you were not be able to use the Text ISAM to
update text files with the following extensions:

- bat
- cmd
- ini
- sys
- inf
- vbs
- js

These are the default extensions that were added to the registry key listed in
the "Resolution" section with the first release of Jet 3.5 SP3. The Value data
for the registry key was:

  bat,cmd,ini,sys,inf,vbs,js

NOTE: The first release of Jet 3.5 SP3 did not provide the use of an exclamation
mark (!). When you place an exclamation mark at the beginning of the Value data,
you can modify only files with the extensions listed. When you do not place an
exclamation mark at the beginning of the Value data, you cannot modify files
with the extension listed. NOTE: Microsoft Access users may receive the
following error when trying to import a text file that is not one of the enabled
extensions:

  Can't Update. Database is read-only.

To resolve the error, either rename the file extension to one of the enabled
extension types or modify the DisabledExtensions registry key using the methods
in this article.


Additional query words: pra

======================================================================
Keywords          : kbdta 
Technology        : kbOfficeSearch kbAudDeveloper kbAccessSearch kbAccess97 kbOffice97Search kbODBCSearch kbAccess97Search kbOffice97 kbODBCAccess350
Version           : WINDOWS:3.5,97
Issue type        : kbbug
Solution Type     : kbpending

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