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              AUSCERT External Security Bulletin Redistribution
                             
           ESB-1999.194 -- Microsoft Security Bulletin (MS99-057)
  Patch Available for "Malformed Security Identifier Request" Vulnerability
                             17 December 1999

===========================================================================

Microsoft Corporation has released the following security bulletin 
concerning a vulnerability in the Windows NT 4.0 Local Security Authority
(LSA). A malformed call to the LsaLookupSids() function may cause the LSA
to crash, thereby preventing the machine from performing useful work.

This vulnerability may be exploited remotely to cause a Denial of Service
(DoS) attack:

       http://www.microsoft.com/security/bulletins/MS99-057.asp

The fix for this vulnerability was also included in the patch mentioned 
in Microsoft Security Bulletin (MS99-056), previously re-distributed 
by AusCERT as ESB-1999.193.

===========================================================================

This security bulletin is provided as a service to AusCERT's members.
As AusCERT did not write the document referenced above, AusCERT has
had no control over its content.  The decision to use any or all
of this information is the responsibility of each user or organisation,
and should be done so in accordance with site policies and procedures.

If you have any questions or need further information, please contact 
Microsoft Corporation directly.

Previous advisories and external security bulletins can be retrieved from:

	http://www.auscert.org.au/Information/advisories.html

If you believe that your system has been compromised, contact AusCERT or
your representative in FIRST (Forum of Incident Response and Security
Teams).

Internet Email: auscert@auscert.org.au
Facsimile:	(07) 3365 7031
Telephone:	(07) 3365 4417 (International: +61 7 3365 4417)
		AusCERT personnel answer during Queensland business hours
		which are GMT+10:00 (AEST).
		On call after hours for emergencies.

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