__________________________________________________________
The U.S. Department of Energy
Computer Incident Advisory Center
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/ | /_\ /
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__________________________________________________________
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
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otherwise, does not necessarily constitute or imply its endorsement,
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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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