DOCUMENT:Q231605 16-MAY-2002 [winnt] TITLE :Malformed Help File Causes Help Utility to Stop Responding PRODUCT :Microsoft Windows NT PROD/VER:winnt:4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 SP4 OPER/SYS: KEYWORDS:kbWinNT4sp6fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server version 4.0, Terminal Server Edition - Microsoft Windows NT Workstation versions 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3, 4.0 SP4 - Microsoft Windows NT Server versions 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3, 4.0 SP4 - Microsoft Windows NT Server, Enterprise Edition versions 4.0, 4.0 SP4 ------------------------------------------------------------------------------- SYMPTOMS ======== A specially-malformed Microsoft Help file may be used to exploit a security vulnerability on a Windows NT-based computer. When a user activates the Windows Help file tool (for example, by pressing the F1 key) this vulnerability may be used to run a program and may cause the Help file tool to stop responding (hang). CAUSE ===== The Help tool parses and displays Help information for programs. The Help information is contained in several file types that are generated by the Microsoft Help Compiler program and are stored (by default) in the %SystemRoot%\Help folder. Users have both Read and Write permissions to this folder by default. An unchecked buffer exists in the Help utility, and a Help file that has been carefully modified could be used to run a program on the local computer using a buffer overrun technique. Because the Help Compiler program's output files do not generate the specific malformation at issue here, this vulnerability could not be accidentally exploited. RESOLUTION ========== Windows NT Server or Workstation 4.0 ------------------------------------ To resolve this problem, obtain the latest service pack for Windows NT 4.0 or the individual software update. For information on obtaining the latest service pack, please go to: - http://www.microsoft.com/Windows/ServicePacks/ -or- - Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack For information on obtaining the individual software update, contact Microsoft Product Support Services. 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: This hotfix can be applied to computers running Windows NT 4.0 Service Pack 4 or Windows NT 4.0 Service Pack 5. Windows NT Server 4.0, Terminal Server Edition ---------------------------------------------- To resolve this problem, obtain the latest service pack for Windows NT Server 4.0, Terminal Server Edition. For additional information, please see the following article in the Microsoft Knowledge Base: Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack STATUS ====== Microsoft has confirmed this to be a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows NT Server version 4.0, Terminal Server Edition Service Pack 6. MORE INFORMATION ================ Computers primarily at risk from this vulnerability are workstations, terminal servers, and other computers that allow users to log on interactively and add or modify Help files. Servers generally do not allow normal users to interactively log on. Note that this vulnerability would affect only the local computer; there is no capability to directly attack a remote computer by means of this vulnerability. For related information on this problem, please visit the Web site at: http://www.microsoft.com/security/bulletins/MS99-015.asp For additional security-related information about Microsoft products, please visit the Web site at: http://www.microsoft.com/security/ Additional query words: ====================================================================== Keywords : kbWinNT4sp6fix Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTW400sp4 kbWinNTW400sp3 kbWinNTW400sp2 kbWinNTW400sp1 kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400sp4 kbWinNTSEnt400 kbWinNTS400sp4 kbWinNTS400sp3 kbWinNTS400sp2 kbWinNTS400sp1 kbWinNTS400search kbWinNTS400 kbNTTermServ400 kbNTTermServSearch Version : winnt:4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 SP4 Hardware : ALPHA x86 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.