__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Center ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Microsoft Remote Procedure Call (RPC) Server Vulnerability [Microsoft Security Bulletin MS01-041] July 30, 2001 17:00 GMT Number L-126 ______________________________________________________________________________ PROBLEM: A malformed RPC request can cause a denial of service. PLATFORM: Those running any of the following products: * Microsoft Exchange Server 5.5 * Microsoft Exchange Server 2000 * Microsoft SQL Server 7.0 * Microsoft SQL Server 2000 * Microsoft Windows NT 4.0 * Microsoft Windows 2000 DAMAGE: The level of damage could range from minor (e.g., the service temporarily hanging) to major (e.g., the service failing in a way that would require the entire system to be restarted). SOLUTION: Apply the patches and proper firewalling as indicated in the bulletin. ______________________________________________________________________________ VULNERABILITY The risk is LOW. Proper firewalling would help minimize the ASSESSMENT: possibility of attacks by Internet-based users. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/l-126.shtml ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS01-041 *****] - ---------------------------------------------------------------------- Title: Malformed RPC Request Can Cause Service Failure Date: 26 July 2001 Software: Exchange Server 5.5, Exchange Server 2000, SQL Server 7.0, SQL Server 2000, Windows NT 4.0, Windows 2000 Impact: Denial of service Bulletin: MS01-041 Microsoft encourages customers to review the Security Bulletin at: http://www.microsoft.com/technet/security/bulletin/MS01-041.asp. - ---------------------------------------------------------------------- Issue: ====== Several of the RPC servers associated with system services in Microsoft Exchange, SQL Server, Windows NT 4.0 and Windows 2000 do not adequately validate inputs, and in some cases will accept invalid inputs that prevent normal processing. The specific input values at issue here vary from RPC server to RPC server. An attacker who sent such inputs to an affected RPC server could disrupt its service. The precise type of disruption would depend on the specific service, but could range in effect from minor (e.g., the service temporarily hanging) to major (e.g., the service failing in a way that would require the entire system to be restarted). Mitigating Factors: ==================== - Proper firewalling would help minimize an affected system's exposure to attack by Internet-based users. In general, a firewall should block access to all RPC services except those that are specifically intended for use by untrusted users. Patch Availability: =================== - A patch is available to fix this vulnerability. Please read the Security Bulletin http://www.microsoft.com/technet/security/bulletin/ms01-041.asp for information on obtaining this patch. Acknowledgment: =============== - Bindview's Razor Team (http://razor.bindview.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 Microsoft Security Bulletin MS01-041 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Microsoft for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Center, 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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