Microsoft Security Bulletin MS01-048

[Microsoft Product Security <secnotif () MICROSOFT COM>]

The following is a Security  Bulletin from the Microsoft Product Security
Notification Service.

Please do not  reply to this message,  as it was sent  from an unattended
mailbox.
                    ********************************

 
-----BEGIN PGP SIGNED MESSAGE-----

- ----------------------------------------------------------------------
Title:      Malformed Request to RPC Endpoint Mapper can Cause RPC
            Service to Fail
Date:       10 September 2001
Software:   Microsoft(r) Windows NT(r) 4.0
Impact:     Denial of service
Bulletin:   MS01-048

Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS01-048.asp.
- ----------------------------------------------------------------------

Issue:
======
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. 

Patch Availability:
===================
 - A patch is available to fix this vulnerability. Please read the 
   Security Bulletin at
   http://www.microsoft.com/technet/security/bulletin/ms01-048.asp
   for information on obtaining this patch.

Acknowledgment:
===============
 - Seiichi Tatsukawa of Rational Software (http://www.rational.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.



-----BEGIN PGP SIGNATURE-----
Version: PGP 7.1

iQEVAwUBO50aKY0ZSRQxA/UrAQFPHgf/YxYPF2gO8Tdqc9GvRoBJacS40wNenPye
avi2L8bsuBnZJEJvhzClyRzeJJqCAjMTgNyiMYz/2Ws9wvI4Ooe7tPvBdKb7KTDI
zRkPcJx0QRXjigxgspgIgo7V1VViH3TIPEwo54p9905uO255oz0siIjOgmmuVgHH
SrPFPyn8rmD7Ic1X343TiyQAx2mLPwaWGmfBJHc+/rgoZIEsgRRL6jX7tLl0NI6C
aQUjKvtHeLl5r246G0dHd+p5J36/ebQscZvM8cw+UjZb3+SGkI+1cvr0bzRwSrYv
Qr9mi8KUvpTyI8dMooTnfDC1tsde726j7noR5Fk+JasLP4CDeq1Wvw==
=J5Cf
-----END PGP SIGNATURE-----

   *******************************************************************
You have received  this e-mail bulletin as a result  of your registration
to  the   Microsoft  Product  Security  Notification   Service.  You  may
unsubscribe from this e-mail notification  service at any time by sending
an  e-mail  to  MICROSOFT_SECURITY-SIGNOFF-REQUEST () ANNOUNCE MICROSOFT COM
The subject line and message body are not used in processing the request,
and can be anything you like.

To verify the digital signature on this bulletin, please download our PGP
key at http://www.microsoft.com/technet/security/notify.asp.

For  more  information on  the  Microsoft  Security Notification  Service
please  visit  http://www.microsoft.com/technet/security/notify.asp.  For
security-related information  about Microsoft products, please  visit the
Microsoft Security Advisor web site at http://www.microsoft.com/security.