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Title:      Flaw in how Outlook 2002 handles V1 Exchange Server 
            Security Certificates could lead to Information 
            Disclosure (812262)
Date:       22 January 2002
Software:   Microsoft Outlook 2002
Impact:     Information Disclosure
Max Risk:   Moderate
Bulletin:   MS03-003

Microsoft encourages customers to review the Security Bulletins at: 
http://www.microsoft.com/technet/security/bulletin/MS03-003.asp
http://www.microsoft.com/security/security_bulletins/MS03-003.asp
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Issue:
======
Microsoft Outlook 2002 provides the facility to encrypt e-mails 
sent between e-mail recipients. Encryption is used to prevent 
parties other than the intended recipients from reading the 
contents of an e-mail. Outlook uses public key certificates to 
facilitate the exchange of the cryptographic keys that are used in 
the encryption process, and Outlook offers a number of different 
options as to what type of certificates can be used. S/MIME 
certificates are the most commonly used (and are not affected by 
the vulnerability that is the subject of this bulletin), but there 
are other certificate options including V1 Exchange Server Security 
certificates. 

A vulnerability exists because there is a flaw in the way Outlook 
2002 handles a V1 Exchange Server Security certificate when using 
it to encrypt e-mail. As a result of this flaw, Outlook fails to 
encrypt the mail correctly and the message will be sent in plain 
text. This could cause the information in the e-mail to be exposed 
when the user believed it to be protected through encryption.

Mitigating Factors:
====================
- -This vulnerability only affects encryption when a V1 Exchange 
 Server Security certificate is used. S/MIME encryption, which is 
 the most widely used form of e-mail encryption used by Outlook, is 
 not affected. 

- -This vulnerability only affects Outlook 2002 and only when sending 
 HTML e-mail.

Risk Rating:
============
 Moderate

Patch Availability:
===================
 - A patch is available to fix this vulnerability. Please read the 
   Security Bulletins at
   http://www.microsoft.com/technet/security/bulletin/ms03-003.asp
   http://www.microsoft.com/security/security_bulletins/ms03-003.asp

   for information on obtaining this patch.

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