AUSCERT External Security Bulletin Redistribution

                  ESB-2003.0822 -- UNIRAS Brief - 645/03
         Microsoft security issue affecting Exchange Server 2003 and 
                          Outlook Web Access (OWA)
                             28 November 2003


        AusCERT Security Bulletin Summary

Product:                SharePoint Services 2.0
                        Exchange Server 2003
                        Outlook Web Access (OWA)
Publisher:              UNIRAS (UK Govt CERT)
Operating System:       Windows 2003
Impact:                 Access Privileged Data
Access Required:        Existing Account

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Microsoft security issue affecting Exchange
Server 2003 and Outlook Web Access (OWA). 


Microsoft has received reports of a security issue affecting Exchange
Server 2003 and Outlook Web Access (OWA). 
The problem occurs when a user installs Windows SharePoint Services 2.0
on top of Exchange Server 2003 and Windows Server 2003. The deployment
causes Kerberos authentication to be disabled in Internet Information
Services (IIS) and can result in the incorrect handling of Outlook Web
Access requests to an Exchange Server.  At worst, this issue could
result in access to mailboxes at random and only to an authenticated
Exchange user in the same organization on the same network.

Microsoft is working with customers to ensure their information is
protected. Microsoft has published two Knowledge Base articles that
detail the problem and instruct customers how to correct and avoid this
issue. Microsoft Product Support has also successfully helped and is
continuing to help customers who have problems.

This information is available at http://support.microsoft.com/?id=832769
and http://support.microsoft.com/?id=832749 

As a general rule, Microsoft recommends customers run Exchange 2003 with
Kerberos enabled in Internet Information Services to achieve the most
secure environment and that is why Windows Server 2003 ships with
Kerberos enabled by default.

Microsoft is committed to keeping customers' information safe and upon
completion of investigating the problem, Microsoft will take the
appropriate action to protect its customers and decide whether providing
a fix and additional mitigation information is warranted. 

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UNIRAS wishes to acknowledge the contributions of Microsoft for the information
contained in this Briefing. 
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