If you set up Spamhalter (or Popfile) you will be able to tell it what to inject in the Subject line of spams.

As a bonus you will also get MUCH less spam and MUCH less work trying to catch spam with CC rules [:)] 

Via content control I have succesfully added an header "X-Spam: Yes" to email identified as spam by spambust.dat (weight>50)
How can I add a string using a global filter rule(?) to the subject of such mails, e.g. Subject: Buy xxxx  => Subject: (SPAM) Buy xxxx

 
Thanks, mel

 

At this point, you can't modify (edit) existing headers in the message using rules. It's an oft-requested feature, though, and will almost certainly make it into the program at some point.

Cheers!

-- David --