Strange mail with number in subject line and body

["paul.johnson8 () gmail com" <paul.johnson8 () gmail com>]

We have received a few strange emails (from Korea and France) which
lists a three character number in the subject line and a different
three digit character number in the body, no attachments.

The sender (from field) has been spoofed and displays the receivers
name (to field).

I did a search on google but could not find any further information.
Has any seen or know where/why these emails are being received?  Maybe
a sdbot infection on zombie PC?

------------------------------------------------------------------------------
This List Sponsored by: Black Hat

Attend the Black Hat Briefings & Training USA, July 29. August 3 in Las Vegas. 
World renowned security experts reveal tomorrow.s threats today. Free of 
vendor pitches, the Briefings are designed to be pragmatic regardless of your 
security environment. Featuring 36 hands-on training courses and 10 conference 
tracks, networking opportunities with over 2,500 delegates from 40+ nations. 

http://www.blackhat.com
------------------------------------------------------------------------------