The following is a Security Bulletin from the Microsoft Product Security
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Microsoft Security Bulletin (MS99-020)
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Patch Available for "Malformed LSA Request" Vulnerability
Originally Posted: June 23, 1999
Summary
=======
Microsoft has released a patch that eliminates a vulnerability that poses a
denial of service threat to Microsoft(r) Windows NT(r) servers and
workstations. A malformed request to the Local Security Authority (LSA)
service will causes the service to stop responding, requiring the computer
to be restarted.
A fully supported patch is available to eliminate the vulnerability, and
Microsoft recommends that affected customers download and install it, if
appropriate.
Issue
=====
Windows NT provides the ability to manage user privileges programmatically
via the Local Security Authority (LSA) API. The API allows a program to
query user names, modify privileges, and change other elements of the
security policy, subject to the program's authorizations.
Certain API methods do not correctly handle certain types of invalid
arguments. The vulnerability is a denial of service threat only, and
service can be restored by restarting the machine. There is no capability
to use this vulnerability to obtain unauthorized services from LSA.
While there are no reports of customers being adversely affected by this
vulnerability, Microsoft is proactively releasing this patch to allow
customers to take appropriate action to protect themselves against it.
Affected Software Versions
==========================
- Microsoft Windows NT 4.0 Workstation
- Microsoft Windows NT 4.0 Server
- Microsoft Windows NT 4.0 Server, Terminal Server Edition, 4.0
What Microsoft is Doing
=======================
Microsoft has released patches that fix the problem identified. The patches
are available for download from the sites listed below in What Customers
Should Do.
Microsoft also 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) article on this
issue:
- Microsoft Knowledge Base (KB) article Q231457,
Malformed Request Causes LSA Service to Hang,
http://support.microsoft.com/support/kb/articles/q231/4/57.asp
(Note: It might take 24 hours from the original posting of
this bulletin for the KB article to be visible in the Web-based
Knowledge Base.)
What Customers Should Do
========================
Microsoft has released patches that fix the problem identified.
Microsoft highly recommends that customers evaluate the degree of
risk that this vulnerability poses to their systems and determine
whether to download and install the patch. The patch can be found at:
- ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa
/NT40/hotfixes-postSP5/LSA3-fix/
NOTE: The above URL has been word-wrapped for readability
More Information
================
Please see the following references for more information related to this
issue.
- Microsoft Knowledge Base (KB) article Q231457,
Malformed Request Causes LSA Service to Hang,
http://support.microsoft.com/support/kb/articles/q231/4/57.asp.
Obtaining Support on this Issue
===============================
If you require technical assistance with this issue, please contact
Microsoft Technical Support. For information on contacting Microsoft
Technical Support, please see
http://support.microsoft.com/support/contact/default.asp.
Acknowledgments
===============
Microsoft acknowledges BindView Corporation (http://www.bindview.com) for
discovering the vulnerability and reporting it to us.
Revisions
=========
- June 23, 1999: Bulletin Created.
For additional security-related information about Microsoft products,
please visit http://www.microsoft.com/security
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WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER
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(c) 1999 Microsoft Corporation. All rights reserved. Terms of Use.
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