Unchecked Print Spooler Buffer May Expose System Vulnerability

ID: Q243649

The information in this article applies to:

Microsoft Windows NT Workstation version 4.0
Microsoft Windows NT Server version 4.0
Microsoft Windows NT Server, Enterprise Edition version 4.0
Microsoft BackOffice Server versions 4.0, 4.5
Microsoft BackOffice Small Business Server versions 4.0, 4.5

SYMPTOMS

When you pass random data to some of the functions in the Windows NT 4.0 print spooler sub-system Application Programming Interface (API) that have unchecked buffers, the print spooler service may stop responding (hang). If the affected API is provided with a specially-malformed argument, it may be possible to bypass the computer security settings and run an unauthorized program using a buffer overrun technique.

The majority of the affected APIs require that the user be a member of the Power Users or Administrators group. However, at least one API is callable by users that have not been assigned extended security permissions. The calls can also be made remotely.

RESOLUTION

A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific problem, Microsoft recommends that you wait for the next Windows NT 4.0 service pack that contains this fix.

To resolve this problem immediately, 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://www.microsoft.com/support/supportnet/overview/overview.asp

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


   Date       Time     Size      File name      Platform
   -------------------------------------------------------------
   10/26/99   03:29p    12,560   Lmmon.dll      x86
   10/26/99   03:29p    18,704   Localmon.dll   x86
   10/27/99   11:52a   140,560   Localspl.dll   x86
   10/26/99   03:13p    48,400   Spoolss.dll    x86
   10/26/99   03:18p    39,184   Spoolss.exe    x86
   10/26/99   03:21p    79,632   Win32spl.dll   x86
   10/26/99   03:14p    20,240   Lmmon.dll      Alpha
   10/26/99   03:27p    32,016   Localmon.dll   Alpha
   10/27/99   11:50a   236,304   Localspl.dll   Alpha
   10/26/99   03:10p    85,776   Spoolss.dll    Alpha
   10/26/99   03:11p    65,808   Spoolss.exe    Alpha
   10/26/99   03:11p   135,952   Win32spl.dll   Alpha

The Intel-based version of this hotfix has been posted to the following Internet location as Q243649.exe:

http://download.microsoft.com/download/winntsrv40/Patch/Spooler-fix/NT4/EN-US/Q243649.exe

The Alpha-based version of this hotfix has been posted to the following Internet location as Q243649.exe:

http://download.microsoft.com/download/winntsrv40/Patch/Spooler-fix/ALPHA/EN-US/Q243649.exe

NOTE: You must be running Service Pack 4 (SP4) or later to apply this fix.

STATUS

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

MORE INFORMATION

For related information on this problem, please visit the following Microsoft Web site:

http://www.microsoft.com/security/bulletins/ms99-047faq.asp

For additional security-related information about Microsoft products, please visit the following Microsoft Web site:

http://www.microsoft.com/security/

Additional query words:

Keywords : kbprint ntsecurity ntsp kbbug4.00 kbfix4.00
Version : winnt:4.0,4.5
Platform : winnt
Issue type : kbprb