Combatting spam caused by mailing lists
12 Sep. 2007
I finally got off my dead butt and decided to play with procmail for my spam. Is it just me, or has spam really increased lately? The SANS storm center leads me to believe spam has actually increased. Stupid NFL spam. Stupid stocks.
Anywho...so, procmail. Today I discovered a really, really, really awesome spam fighting combination, which is probably super obvious, but having just implemented it I am only now basking in its glory. I've been using the first 3 steps below for a long time now, but for step 4 I was using really elaborate Pine filters. The Pine filters were pretty weak, but replacing them with a single procmail recipe really made this killer.
- (1) Create a personal e-mail account and share it only with people that you trust implicitly. Do not share it with people whom you believe are liable to get viruses on their computers (i.e. your parents and friends who like to open Britney Spears attachments). Do not ever, ever, ever use it to sign up for things on the internet. Never enter it into any form whatsoever. Do not use it on a website. Protect it with your life.
- (2) Create a second e-mail account and do all the things I cautioned against in #1, but use this new, "trash" account to do them.
- (3) Create a third account and use it only to sign up for mailing and discussion lists, if you are into that sort of thing.
- (4) Create the following procmail recipe:
:O:
* ^To: e-mail.address@rule3above.com
spam
So, in plain English, signing up for e-mail lists is a sure guarantee that you will receive spam. But....e-mail lists send the messages "To" the list, not "to" your e-mail address. That means that if the e-mail address you use for mailing lists appears in the "to" field of an e-mail, it has a 99% chance of being spam. The recipe above shunts all e-mails in this category to a folder named "spam," where you can quickly skim through to make sure none of the messages were for you. It also means that virtually no actual spam will remain in your inbox, at least not that is for your mailing list address. Spam created by moronic friends who open e-mail attachments would require a different rule.
I love this recipe.