__________________________________________________________

                       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:
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    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
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