__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Center ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN RPC Endpoint Mapper Vulnerability [Microsoft Security Bulletin MS01-048] September 12, 2001 18:00 GMT Number L-142 ______________________________________________________________________________ PROBLEM: A vulnerability exist where a malformed request to RPC endpoint mapper could cause a denial of service. PLATFORM: Microsoft Windows NT 4.0 DAMAGE: If exploited this vulnerability could cause a denial of service. SOLUTION: Apply available patch or block port 135 at the firewall. ______________________________________________________________________________ VULNERABILITY The risk is LOW. The affected port should be blocked at the ASSESSMENT: firewall. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/l-142.shtml ORIGINAL BULLETIN: http://www.microsoft.com/technet/treeview /default.asp?url=/technet/security/bulletin /MS01-048.asp PATCHES: http://www.microsoft.com/Downloads /Release.asp?ReleaseID=32503 ______________________________________________________________________________ [***** Start Microsoft Security Bulletin MS01-048 *****] Microsoft Security Bulletin MS01-048 Malformed Request to RPC Endpoint Mapper can Cause RPC Service to Fail Originally posted: September 10, 2001 Summary Who should read this bulletin: System administrators using Microsoft® Windows NT® 4.0 Impact of vulnerability: Denial of service. Recommendation: System administrators should apply the patch to servers that offer RPC-based services. Affected Software: Microsoft Windows NT 4.0 Technical details Technical description: The RPC endpoint mapper allows RPC clients to determine the port number currently assigned to a particular RPC service. The Windows NT 4.0 endpoint mapper contains a flaw that causes it to fail upon receipt of a request that contains a particular type of malformed data. Because the endpoint mapper runs within the RPC service itself, exploiting this vulnerability would cause the RPC service itself to fail, with the attendant loss of any RPC-based services the server offers, as well as potential loss of some COM functions. Normal service could be restored by rebooting the server. Mitigating factors: Standard security recommendations call for port 135 – the port on which the RPC endmapper operates – to be blocked at the firewall. If this were done, Internet-based attackers would not be able to exploit this vulnerability. Vulnerability identifier: CAN-2001-0662 Tested Versions: Microsoft tested Windows NT 4.0, Windows 2000, and Windows XP to assess whether they are affected by these vulnerabilities. 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 Workstation, Windows NT 4.0 Server, and Windows NT 4.0 Server, Enterprise Edition: http://www.microsoft.com/Downloads/Release.asp?ReleaseID=32503 Windows NT 4.0 Server, Terminal Server Edition: To be released shortly Acknowledgments: Microsoft thanks Seiichi Tatsukawa of Rational Software (http://www.rational.com) for reporting this issue to us and working with us to protect customers. Support: Microsoft Knowledge Base article Q305399 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 (September 10, 2001): Bulletin Created. [***** End Microsoft Security Bulletin MS01-048 *****] _______________________________________________________________________________ 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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