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Q250998: Access Violation in Cmd.exe in Long Batch Files Using "FOR /F"

Article: Q250998
Product(s): Microsoft Windows NT
Version(s): WINDOWS:2000; winnt:4.0
Operating System(s): 
Keyword(s): kbWin2000PreSP1Fix kbWinNT400PreSP7Fix
Last Modified: 08-MAY-2002

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The information in this article applies to:

- Microsoft Windows NT Workstation version 4.0 
- Microsoft Windows NT Server, Enterprise Edition version 4.0 
- Microsoft Windows NT Server version 4.0 
- Microsoft Windows 2000 Advanced Server 
- Microsoft Windows 2000 Professional 
- Microsoft Windows 2000 Server 
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SYMPTOMS
========

When you are running complex batch files for a long time (to run routine jobs,
monitor services, and so on), and the batch files contain the "for /f" command
to process files line-by-line and run commands using the line contents as
parameters, you may receive "access violation" and "access denied" error
messages in Cmd.exe


CAUSE
=====

When you run the batch files for a long time, the reuse of memory areas by the
program is more likely. In this case, the memory is not "nulled out" by the
operating system. The algorithm used by Cmd.exe to extract tokens used as
parameters for the command in the "for /f" command is vulnerable to reused
memory.

RESOLUTION
==========

Windows 2000
------------

To resolve this problem, obtain the latest service pack for Windows 2000. For
additional information, please see the following article in the Microsoft
Knowledge Base:

  Q260910 How to Obtain the Latest Windows 2000 Service Pack



Windows NT 4.0
--------------

A supported fix is now available from Microsoft, but it is only intended to
correct the problem described in this article and should be applied only to
systems 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 on support costs, please go to the following address on the World
Wide Web:

  http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

NOTE: In special cases, charges that are normally incurred for support calls may
be canceled, if a Microsoft Support Professional determines that a specific
update will resolve your problem. Normal support costs will apply to additional
support questions and issues that do not qualify for the specific update in
question.

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

  Date       Time     Size      File name   Platform
  --------------------------------------------------
  01/25/00   08:51a   208,144   Cmd.exe     x86
  01/25/00   08:50a   357,648   Cmd.exe     Alpha



WORKAROUND
==========

This problem is aggregated by the changes in Heap Manager introduced in Windows
NT 4.0 Service Pack 4. You should be able to avoid the problem by using the
workaround described in the following Microsoft Knowledge Base article:

  Q195009 Application Access Violation or Hang After Applying SP4

STATUS
======

Windows 2000
------------

Microsoft has confirmed this to be a problem in Windows 2000. This problem was
first corrected in Windows 2000 Service Pack 1.

Windows NT 4.0
--------------

Microsoft has confirmed this to be a problem in Windows NT 4.0.

Additional query words:

======================================================================
Keywords          : kbWin2000PreSP1Fix kbWinNT400PreSP7Fix 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbwin2000AdvServ kbwin2000AdvServSearch kbwin2000Serv kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400 kbWinNTS400search kbWinNTS400 kbwin2000ServSearch kbwin2000Search kbwin2000ProSearch kbwin2000Pro kbWinAdvServSearch
Version           : WINDOWS:2000; winnt:4.0
Hardware          : ALPHA x86
Issue type        : kbbug
Solution Type     : kbfix

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