Date: Mon, 10 Jan 2011 12:00:00 -0500
From: phisher@evil.com
To: user@example.com
Subject: Please look at this attachment!
Content-Type: multipart/mixed; boundary="BOUNDARY"

This is a multi-part message in MIME format.
--BOUNDARY
Content-Type: text/html

See below.
--BOUNDARY
Content-Type: message/rfc822

Date: Mon, 10 Jan 2011 12:00:00 -0500
From: phisher@evil.com
To: user@example.com
Subject: Please click on this link!
Content-Type: text/html

<form action="http://localhost/download-me"><input></form>
--BOUNDARY--