Ever heard of a "Joe job?"  (Google it.)  I hadn't.  Basically it's an attack on someone who has an E-mail account; what you do is send an enormous spam with the target's address as the "From:" address. (It's pathetically easy to forge a "From:" address, which is why you always seem to be getting E-mails from PayPal and Amazon asking you to type in your password to verify your account or something. Hint: don't.)

Then the target gets a bunch of hate mail from the recipients of the spam, but more importantly, if any addresses are not valid, they get notifications from the server saying "This user doesn't exist" or something like that. You've probably gotten one of these if you ever sent E-mail to a bad address -- either mistyped it, or had an old E-mail address for someone.

When millions of E-mails are sent "by you," you get thousands and thousands of returned e-mails sent to bad addresses.  That's the "Joe job."  Joe was a guy who was an original target of one of these attacks; the Google links have more information if you're interested.

Anyway, someone has been using my E-mail address as a forged return address for thousands of E-mail messages sent to Korea, and one Korean ISP has decided to block further E-mail from me because I've been sending too much. Thus, it's not just the bad E-mail addresses for which I'm getting return notifications, it's even the good ones. Thankfully, their server batches the rejection message for every 25 messages or so. But still, I've been getting one notification every 2 minutes or so for about 10 days. This tends to fill up your mailbox quickly. When I try to check my E-mail using web mail (I can't connect to my mail server from my client site), I have hundreds and hundreds of messages from this server. And I'm going out of town for a few days soon, and would be coming home to literally thousands of E-mails, maybe tens of thousands, if it doesn't stop.

I tried to mail the mail server administrator (in English), but haven't heard back (assuming that my spam filters didn't intercept the reply as spam, which is possible, given that I've gotten thousands of mail messages marked as junk from them, since they are kind enough to include a copy of my message with each failure notice).

So today I set up procmail on my FreeBSD mail server and wrote a custom rule to start filtering out these replies. I stayed home from snowboarding today to get work done -- but I just spent about 2 hours learning procmail, and not doing work, so that I could stop the flood of messages. Now I guess I should get back to work, although there's not much time left in the day.

I guess I should be happy that I learned a skill.

Back to work.