__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft HyperTerminal Buffer Overflow October 19, 2000 15:00 GMT Number L-008 _____________________________________________________________________________ PROBLEM: Microsoft has identified a vulnerability in the HyperTerminal application that is installed, by default, on several Microsoft operating systems. PLATFORM: Windows 98, 98SE, Windows ME, Windows NT, and Windows 2000 DAMAGE: The vulnerability may allow a malicious user to execute arbitrary code on another user's system. SOLUTION: Apply appropriate patches as indicated below. _____________________________________________________________________________ VULNERABILITY Risk is MEDIUM. The vulnerability affects system security and ASSESSMENT: is publicly known. Patches should be applied as soon as possible. _____________________________________________________________________________ [****** Start of Microsoft Bulletin ******] - ---------------------------------------------------------------------- - - Title: HyperTerminal Buffer Overflow Vulnerability Released: 18 October 2000 Revised: 24 May 2001 (version 2.0) Software: HyperTerminal on Windows 98, 98SE, Windows ME, Windows NT 4.0, Windows 2000 Impact: Privilege Elevation Bulletin: MS00-079 Microsoft encourages customers to review the Security Bulletin at: http://www.microsoft.com/technet/security/bulletin/MS00-079.asp. - ---------------------------------------------------------------------- - - Reason for Revision: ==================== Microsoft has re-released this bulletin to inform customers of the availability of an updated set of patches to address both the original and a second vulnerability identified in HyperTerminal. Information about the second issue is discussed in the Issue section below and in the security bulletin referenced above. Issue: ====== The HyperTerminal application is a communications utility that installs by default on all versions of Windows 98, 98SE, Windows ME, Windows NT 4.0, and Windows 2000. The product contains two unchecked buffers through which an attacker could potentially cause code of her choice to run on another user's machine: - One resides in a section of the code that processes Telnet URLs. If a user opened an HTML mail that contained a particular type of malformed Telnet URL, and HyperTerminal were configured as the default Telnet client, it would trigger the buffer overrun. HyperTerminal is the default Telnet client on Windows 98, 98SE and ME. It is not the default Telnet client on Windows 2000. - The other resides in a section of the code that processes session files - files that enable HyperTerminal users to specify session parameters such as the connection method and the destination host. If a user opened a session file that contained a particular type of malformed information, it would trigger the buffer overrun. Although HyperTerminal ships as part of several Microsoft products, it was developed by a third party. Additional information on the vulnerability and a patch for their full version product, HyperTerminal Private Edition, is available from their web site at www.hilgraeve.com Mitigating Factors: ==================== The malicious user must entice another user into clicking on a specially-formed telnet URL or opening a malformed HyperTerminal session file. Patch Availability: =================== - A patch is available to fix this vulnerability. Please read the Security Bulletin http://www.microsoft.com/technet/security/bulletin/ms00-079.asp for information on obtaining this patch. Acknowledgment: =============== - Luciano Martins of USSR Labs (www.ussrback.com) - ---------------------------------------------------------------------- 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. [****** End of Microsoft Bulletin ******] _____________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft for the information contained in this bulletin. _____________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. 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Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. 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