__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Buffer Overrun in Microsoft Windows Could Lead to Data Corruption [Microsoft Security Bulletin MS03-024] July 10, 2003 17:00 GMT Number N-115 ______________________________________________________________________________ PROBLEM: A flaw exists in the way that the server validates the parameters of an SMB (Server Message Block) packet. The server is not properly validating the buffer length established by the packet. If the client specifies a buffer length that is less than what is needed, it can cause the buffer to overrun. SOFTWARE: * Microsoft Windows NT Server 4.0 * Microsoft Windows NT Server 4.0, Terminal Server Edition * Microsoft Windows 2000 * Windows XP Professional DAMAGE: By sending a specially crafted SMB packet request, an attacker could cause a buffer overrun to occur. If exploited, this could lead to data corruption, system failure, or in the worst case, allow an attacker to run code of their choice. SOLUTION: Apply patches as stated in Microsoft's security bulletin. ______________________________________________________________________________ VULNERABILITY The risk is MEDIUM. In order to exploit this vulnerability, an ASSESSMENT: attacker would need a valid user account, and be authenticated by the server prior to sending an SMB packet to it. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/n-115.shtml ORIGINAL BULLETIN: http://www.microsoft.com/technet/treeview/ default.asp?url=/technet/security/bulletin/MS03-024.asp ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS03-024 *****] Microsoft Security Bulletin MS03-024 Buffer Overrun in Windows Could Lead to Data Corruption (817606) Originally posted: July 09, 2003 Summary Who should read this bulletin: Customers using Microsoft® Windows® NT, Microsoft Windows 2000, or Microsoft Windows XP Impact of vulnerability: Allow an attacker to execute code of their choice Maximum Severity Rating: Important Recommendation: Administrators should consider installing the patch. Affected Software: * Microsoft Windows NT Server 4.0 * Microsoft Windows NT Server 4.0, Terminal Server Edition * Microsoft Windows 2000 * Windows XP Professional Not Affected Software: * Microsoft Windows Server 2003 Technical details Technical description: Server Message Block (SMB) is the Internet Standard protocol that Windows uses to share files, printers, serial ports, and to communicate between computers using named pipes and mail slots. In a networked environment, servers make file systems and resources available to clients. Clients make SMB requests for resources, and servers make SMB responses in what’s described as a client server request-response protocol. A flaw exists in the way that the server validates the parameters of an SMB packet. When a client system sends an SMB packet to the server system, it includes specific parameters that provide the server with a set of “instructions.” In this case, the server is not properly validating the buffer length established by the packet. If the client specifies a buffer length that is less than what is needed, it can cause the buffer to be overrun. By sending a specially crafted SMB packet request, an attacker could cause a buffer overrun to occur. If exploited, this could lead to data corruption, system failure, or—in the worst case—it could allow an attacker to run the code of their choice. An attacker would need a valid user account and would need to be authenticated by the server to exploit this flaw. Mitigating factors: * Windows Server 2003 is not affected by this vulnerability. * By default, it is not possible to exploit this flaw anonymously. The attacker would have to be authenticated by the server prior to attempting to send a SMB packet to it. * Blocking port 139/445 at the firewall will prevent the possibility of an attack from the Internet. Severity Rating: Windows NT Server 4.0 Important Windows NT Server 4.0, Terminal Server Edition Important Windows 2000 Important Windows XP Professional Important The above assessment is based on the types of systems affected by the vulnerability, their typical deployment patterns, and the effect that exploiting the vulnerability would have on them. Vulnerability identifier: CAN-2003-0345 Tested Versions: Microsoft tested Windows NT Server 4.0, Windows NT Server 4.0, Terminal Services Edition, Windows 2000, Windows XP and Windows Server 2003 to assess whether they are affected by this vulnerability. Previous versions are no longer supported, and may or may not be affected by these vulnerabilities. Patch availability Download locations for this patch * Windows NT 4.0 Server * Windows NT 4.0, Terminal Server Edition * Windows 2000 Server * Windows XP 32 bit Edition * Windows XP 64 bit Edition Additional information about this patch Installation platforms: This patch can be installed on systems running: * Windows NT Server 4.0: The Windows NT Server 4.0 patch can be installed on systems running Windows NT Server 4.0 Service Pack 6a. * Windows NT Server, Terminal Server Edition: The Windows NT Server, Terminal Server Edition patch can be installed on systems running Windows NT Server, Terminal Server Edition Service Pack 6. * Windows 2000: The Windows 2000 patch can be installed on systems running Windows 2000 Service Pack 3. * Windows XP: The patch for Windows XP can be installed on systems running Windows XP Gold or Windows XP Service Pack 1. Inclusion in future service packs: * The fix for this issue is included in Service Pack 4. * The fix for this issue will be included in Windows XP Service Pack 2. Reboot needed: Yes Patch can be uninstalled: Yes Superseded patches: None. Verifying patch installation: * Windows NT 4.0: To verify that the patch has been installed on the machine, confirm that all files listed in the file manifest in Knowledge Base article 817606 are present on the system. * Windows NT 4.0 Terminal Server Edition: To verify that the patch has been installed on the machine, confirm that all files listed in the file manifest in Knowledge Base article 817606 are present on the system. * Windows 2000: To verify that the patch has been installed on the machine, confirm that the following registry key has been created on the machine: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows 2000\SP4\Q817606. To verify the individual files, use the date/time and version information provided in the following registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Updates\Windows 2000\SP4\Q817606\Filelist. * Windows XP: * If installed on Windows XP Gold: To verify that the patch has been installed, confirm that the following registry key has been created on the machine: HKLM\Software\Microsoft\Updates\Windows XP\SP1\Q817606. To verify the individual files, use the date/time and version information provided in the following registry key: HKLM\Software\Microsoft\Updates\Windows XP\SP1\Q817606\Filelist. * If installed on Windows XP Service Pack 1: To verify that the patch has been installed, confirm that the following registry key has been created on the machine: HKLM\Software\Microsoft\Updates\Windows XP\SP2\Q817606. To verify the individual files, use the date/time and version information provided in the following registry key: HKLM\Software\Microsoft\Updates\Windows XP\SP2\Q817606\Filelist. Caveats: None Localization: Localized versions of this patch are available at the locations discussed in “Patch Availability”. Obtaining other security patches: Patches for other security issues are available from the following locations: * Security patches are available from the Microsoft Download Center, and can be most easily found by doing a keyword search for "security_patch". * Patches for consumer platforms are available from the WindowsUpdate web site Other information: Acknowledgments Microsoft thanks Jeremy Allison and Andrew Tridgell, Samba Team for reporting this issue to us and working with us to protect customers. Support: * Microsoft Knowledge Base article 817606 discusses this issue and will be available approximately 24 hours after the release of this bulletin. Knowledge Base articles can be found on the Microsoft Online Support web site. * Technical support is available from Microsoft Product Support Services. There is no charge for support calls associated with security patches. Security Resources: The Microsoft TechNet Security Web Site provides additional information about security in Microsoft products. Disclaimer: 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. Revisions: * V1.0 July 09, 2003: Bulletin Created. [***** End Microsoft Security Bulletin MS03-024 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft Corporation 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. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. 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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