[8616] in bugtraq
Microsoft Security Bulletin (MS98-017)
daemon@ATHENA.MIT.EDU (Aleph One)
Fri Nov 20 19:43:24 1998
Date: Fri, 20 Nov 1998 18:22:54 -0600
Reply-To: Aleph One <aleph1@DFW.NET>
From: Aleph One <aleph1@DFW.NET>
To: BUGTRAQ@NETSPACE.ORG
---------- Forwarded message ----------
Date: Fri, 20 Nov 1998 15:58:59 -0800
From: Microsoft Product Security <secnotif@MICROSOFT.COM>
To: MICROSOFT_SECURITY@ANNOUNCE.MICROSOFT.COM
Subject: Microsoft Security Bulletin (MS98-017)
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.
********************************
Microsoft Security Bulletin (MS98-017)
--------------------------------------
Patch Available for "Named Pipes Over RPC" Issue
Originally Posted: November 19, 1998
Summary
=======
Microsoft has released a patch that fixes a vulnerability in the way
Microsoft (r) Windows NT (r) 4.0 handles named pipes over the Remote
Procedure Call (RPC) services. An attacker could create a denial of service
situation on a Windows NT 4.0 system by opening multiple named pipe
connections to RPC services and sending random data.
A fully supported fix for this problem is available. As detailed below in
What Customers Should Do, Microsoft recommends that customers evaluate the
risk that this vulnerability poses to their systems and apply the patch if
appropriate.
Issue
=====
The underlying problem is the way that Windows NT 4.0 attempts to shut down
invalid named pipe RPC connections. An attacker could exploit this problem
to create a denial of service condition by opening multiple named pipe
connections and sending random data. When the RPC service attempts to close
the invalid connections, the service consumes all CPU resources and memory
use grows considerably, which may result in the system hanging. This is a
denial of service vulnerability only; there is no risk of compromise or loss
of data from the attacked system.
Different attack programs may target different system services. Two of the
services typically targeted are the SPOOLSS and LSASS system service
processes.
Affected Software Versions
==========================
- Microsoft Windows NT Workstation 4.0
- Microsoft Windows NT Server 4.0
- Microsoft Windows NT Server 4.0, Enterprise Edition
- Microsoft Windows NT Server 4.0, Terminal Server Edition
What Microsoft is Doing
=======================
On November 19 Microsoft released a patch that fixes the problem identified.
This patch is available for download from the sites listed below.
Microsoft has sent this security bulletin to customers
subscribing to the Microsoft Product Security Notification Service
(see http://www.microsoft.com/security/services/bulletin.asp for
more information about this free customer service).
Microsoft has published the following Knowledge Base (KB) articles on this
issue:
- Microsoft Knowledge Base (KB) article Q195733, Denial
of Service in Applications Using Named Pipes Over RPC
http://support.microsoft.com/support/kb/articles/q195/7/33.asp
(Note: It might take 24 hours from the original posting of
this bulletin for the updated KB article to be visible in the
Web-based Knowledge Base.)
Microsoft has posted hot fixes to address this problem:
- Fix for X86 version of Microsoft Windows NT Workstation 4.0,
Microsoft Windows NT Server 4.0,
Microsoft Windows NT Server 4.0, Enterprise Edition
ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes
/usa/NT40/hotfixes-postSP4/nprpc-fix/nprpcfxi.exe
(Note: the above URL has been wrapped for readability)
- Fix for Alpha version of Microsoft Windows NT Workstation 4.0,
Microsoft Windows NT Server 4.0,
Microsoft Windows NT Server 4.0, Enterprise Edition
ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes
/usa/NT40/hotfixes-postSP4/nprpc-fix/nprpcfxa.exe
(Note: the above URL has been wrapped for readability)
- Fix for Microsoft Windows NT Server 4.0, Terminal Server
Edition - This fix will be released shortly. When it is
available, http://www.microsoft.com/security will carry an
announcement that provides the location of the fix.
What customers should do
========================
The patch for this vulnerability is fully supported. However, it has not
been fully regression tested and should only be applied to systems
determined to be at risk of attack. A fully regression-tested version of the
patch will be available as part of the next Windows NT service pack.
Microsoft recommends that customers evaluate the degree of risk that this
vulnerability poses to their systems, based on physical accessibility,
network and Internet connectivity, and other factors, and determine whether
the appropriate course of action is to apply the patch or wait for the next
service pack.
More Information
================
Please see the following references for more information related to this
issue.
- Microsoft Security Bulletin 98-017, Patch Available for Named
Pipes Transport Issue (the Web-posted version of this bulletin),
http://www.microsoft.com/security/bulletins/ms98-017.asp.
- Microsoft Knowledge Base (KB) article Q195733, Denial of Service
in Applications Using Named Pipes Over RPC
http://support.microsoft.com/support/kb/articles/q195/7/33.asp
Obtaining Support on this Issue
===============================
This is a supported patch. If you have problems installing this
patch or require technical assistance with this patch, please
contact Microsoft Technical Support. For information on contacting
Microsoft Technical Support, please see
http://support.microsoft.com/support/contact/default.asp
Acknowledgements
================
Microsoft wishes to acknowledge the issue was reported by Mnemonix
and the contributions of Internet Security Systems, Inc.
(http://www.iss.net) for investigating the problem with us.
Revisions
=========
- November 20, 1998: Bulletin Created
For additional security-related information about Microsoft products,
please visit http://www.microsoft.com/security
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