Outlook and IE for Mac
Reported December 22, 1999 by Microsoft
According to Microsoft"s bulletin on the matter, "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."
Discovered by Microsoft