Stupid spammer using same pattern in from ids

[Ramprasad <ra...@netcore.co.in>]

I thought all the stupid spammers were already eliminated. But now there
is another full generation alive

These spammers use specific patterns for their from-ids that makes
themselves too obvious. It took us quite a while to find out what was
hammerring us but Now I am blocking all these spams right at the MTA 
(postfix pcre tables ) 

last week it was something like 
/^fbi.+war@/

Now it is 
/^daf.+cpu@/

I grep my maillogs and feel pleased I have blocked around 10-20 spams a
sec ( we get 6-7 million mails a day ) booted at the gate

Any idea why anyone would use such specific patterns ? 

Thanks
Ram