Random Hostnames?

[Max Kipness]

Has anybody dealt with spam email addresses like:
 
0w72ibo4i4w2 at hotmail.com
59unzwyb2b at aol.com
 
I figure if I add these to the blacklist it would do no good as these
are probably randomly generated by some program. And as much as I'd like
to ban the entire domains of aol.com and hotmail.com, I can't do this.
 
Is there anyway of added something like regular expressions to pick out
hostnames with patterns like this? Has anybody tackled this before? And
if so, how.
 
Thanks,
Max
 
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