Sunday, October 28, 2007

Of Course, It Had To Be A Webshield

In an earlier blog post, I mentioned that I would buy a round of drinks the first time I saw an attempt to deliver a message with both the From: and To: addresses already on my spammer baiting list.

In fact it happened very soon afterwards, and as luck, misfortune or just plain old incompetence would have it, that message apparently came from a WebShield appliance not too far from here:

Oct 17 23:03:52 skapet spamd[20795]: connected (6/4)
Oct 17 23:04:03 skapet spamd[20795]: (GREY)
<> -> <>
Oct 17 23:04:03 skapet spamd[20795]: disconnected
after 11 seconds.
Oct 17 23:19:21 skapet spamd[20795]: connected (4/3)
Oct 17 23:19:32 skapet spamd[20795]: (GREY)
<> -> <>
Oct 17 23:19:32 skapet spamd[20795]: disconnected
after 11 seconds.
Oct 17 23:30:30 skapet spamd[20795]: connected (4/4),
lists: spamd-greytrap
Oct 17 23:34:14 skapet spamd[20795]: (BLACK)
<> -> <>
Oct 17 23:35:58 skapet spamd[20795]: From:
Oct 17 23:35:58 skapet spamd[20795]:
To: <>
Oct 17 23:35:58 skapet spamd[20795]:
Subject: Returned Mail: Error During Delivery
Oct 17 23:37:00 skapet spamd[20795]:
disconnected after 390 seconds. lists: spamd-greytrap
Oct 17 23:57:18 skapet spamd[20795]:
connected (6/6), lists: spamd-greytrap

I sent the operators at that site a polite message right away, pointing out the misconfiguration. Two weeks later I have seen no response other than the automatic acknowledgement, but it looks like the machine has managed to get itself automatically whitelisted in the meantime. So perhaps they found the button that actually does something.

Since my last blog post I have completed the book, and I expect the last bit of proofing to be done during the coming week. Then a few other necessary processes, and physical copies available for mid December if all goes well. With the cover in place, it looks like it's become attractive and popular over at in its various categories. The BSD category there looks pretty No Starch dominated at the moment.

That can not be a bad thing. It's been a real pleasure working with the people at No Starch Press. If you think you want write a tech book, they should be on the list of publishers to contact with your proposal.

While all this was happening, the spammer baiting operation seems to have reached a critical mass of sorts. With roughly 7,200 addresses in the spamtrap list there are several hundred bait addresses for each real one in those domains taken together, so it's extremely unlikely that the spammers will ever get a chance to try delivery to a real address before they hit the tar pit. Over the last couple of weeks, my gateways have had anywhere between 2,500 and 4,000 hosts in the local spamd-greytrap, and anywhere from 0 to about 300 spambots pushing bytes into the tar pits at any time. It's fun to watch (some of the bots labor through the bait list from top to bottom), and the net effect is, well, we're not seeing much spam.

I think I've mentioned it before, but it bears repeating: To naive spammers and the tools they use, spamd looks like an open relay. Spamd never actually delivers any messages, but this


says that whoever operates (according to whois, likely located in or near Buenos Aires, Argentina), is unable to tell the difference between an open relay and spamd's 451 and subsequent "this is going to hurt you more than it hurts me" messages.

Another variation on that theme is what I think is some sort of amateurish relay testing, which typically produces anywhere from five hundred to a thousand greylist entries of the type


where the From parts are made up of host names and IP addresses in our local net, including in this case, the host name for one of our laser printers. Those floods have tended to swell the bait list a bit, even if I strip out the invalid @<IP address> ones.

Spamd makes the naive relay testers think we have a whole network of open relays, and we harvest the noise they generate to lead the spambots to the tarpit. That's pretty close to a hands-off spammer repellent for us, and a serious auto-LART for the spammers.

OpenCON is sneaking up on us in a month's time, and we're heading for Venice with a refreshed tutorial session. See you there!

PS - [non-IT PS coming up] Bergen's football (soccer) team SK Brann has just won the national league for the first time in 44 years. With one game to go before end of season they are so far ahead in points there is no way any other team will be able to catch up. The town is predictably going gaga over the event, and we joined the thousands at the central Festplassen square for the city sponsored celebration tonight. I'm surprised how many songs have been written about that team and how everybody around me seened to know every last word of the lyrics. Good fun, ending with fireworks.