Opening the attachment (which Sophos detects as Troj/JSRedir-BO) redirects your browser to a third-party site. In our testing that has been a website selling online medications - one of the infamous Candian Pharmacy websites.
But as you're redirected to that online drugs store, you can also be hit by an exploit which attempts to load a booby-trapped PDF and slap you with an infected EXE file via some Java exploits.
The latest disguise being used in this spam campaign is a subject line of "adultfriendfinder new messages" with a file attached called adultfriendfinder.html. We are seeing many of these messages in our global network of spam traps right now.
As you can see in the snapshot above, we're also seeing more romantically-themed variants of the campaign (well, it's hard not to be more romantic than AdultFriendFinder, right?) with an attachment called loveletter.html.
It's been more than ten years since we warned you to be careful of unsolicited loveletters arriving in your inbox. The rules remain the same - be careful about what files you open on your computer, especially when they look as suspicious as this.