Reported April 11, 2005 by iDEFENSE
Microsoft Outlook (not Microsoft Outlook Express)
Due to the way Outlook and OWA parse From header fields, it's possible to change the field so that the email message appears to come from a different address.
Examine all the message's header fields to determine who a message actually came from.
iDEFENSE reports that Microsoft said it might implement a fix in a future service pack but that a security bulletin won't be released for this issue.