[Mailman-Users] ISO speciific RegExp to filter/discard bot subscribe requests

[Steven D'Aprano]

On Sun, Aug 30, 2015 at 02:06:26AM -0700, Nelson Kelly wrote:
[...]
> Inserted the above recommended RegExp string into the ban_list, and 
> within minutes subscribe request bot spam began showing up in the mod 
> queue.
> 
> All the new spams appear to be of a slightly different format from which 
> I described in the OP.
> 
> blahblah+blah-blah-blah-blah-12345678 at gmail.com
> blah_12_34+blah-blah-blah-blah-12345678 at hotmail.com

Try this regex instead:

^.*\+.*?\d{3,}@


The meaning of it is:

^	start of string
.*	any number of characters
\+	a literal plus sign
.*?	any number of characters (non-greedy)
\d{3,}	at least three digits
@	a literal at sign


I'm not sure if the difference between "non-greedy" .*? and "greedy" .* 
is important in this case.

Good luck!



-- 
Steve