Microsoft Security Bulletin MS99-060
Patch Available for "HTML Mail Attachment" Vulnerability
Originally Posted: December 22, 1999
Microsoft has released a patch that addresses two issues:
- It eliminates a security vulnerability in the Microsoft® Outlook Express mail client for Macintosh systems. The vulnerability could allow attachments to HTML mails to be automatically downloaded onto the user's computer.
- It provides replacements for several digital certificates that are included in Internet Explorer for Macintosh, and will expire on December 31, 1999.
Frequently asked questions regarding this patch can be found at http://www.microsoft.com/technet/security/bulletin/fq99-060.mspx.
There are two issues here. The first is a security vulnerability found in Outlook Express 5. By design, when an HTML mail is received, the mail content is downloaded onto the user's machine and processed. However, attachments to the mail should not be downloaded unless the user requests it. A flaw in Outlook Express 5 for Macintosh causes it to download all content, including attachments. The vulnerability does not provide a way for a malicious user to launch the downloaded attachments.
The second issue involves several digital certificates that are included in Internet Explorer 4.5 for Macintosh. These certificates are due to expire on December 31, 1999. The patch provides updated certificates, and also adds support for X509 V3 certificates. There is no security vulnerability associated with this issue; Microsoft is simply providing the replacement certificates and X.509 V3 support as a community service.
It is important to note that both the security vulnerability and the certificate expiration issue affect only Outlook Express and Internet Explorer on the Macintosh; the Windows versions of these products are not affected.
Affected Software Versions
- Microsoft Internet Explorer 4.5 for Macintosh
- Microsoft Outlook Express 5.0 for Macintosh (available as a stand-alone product or bundled with Internet Explorer 5.0 for Macintosh)
Vulnerability Identifier: CVE-2000-0036
NOTE: Additional security patches are available at the Microsoft Download Center
Please see the following references for more information related to this issue.
- Frequently Asked Questions: Microsoft Security Bulletin MS99-060, http://www.microsoft.com/technet/security/bulletin/fq99-060.mspx.
- Internet Explorer 4.5 Security Issue, http://www.microsoft.com/mac/default.aspx.
- Microsoft Knowledge Base (KB) article 249082, Outlook Express 5 for Macintosh Automatically downloads HTML Mail Attachments, http://support.microsoft.com/default.aspx?scid=kb;en-us;249082&sd=tech.
(Note: It may take 24 hours from the original posting of this bulletin for this KB article to be visible.)
- Microsoft Security web site, http://www.microsoft.com/technet/security/default.mspx.
Obtaining Support on this Issue
This is a fully supported patch. Information on contacting Microsoft Technical Support is available at http://support.microsoft.com/contactussupport/?ws=support.
- December 22, 1999: Bulletin Created.
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