Spamhaus comments on subscription attack

Steve Linford, CEO of Spamhaus commented on my blog post about the current listings. I’m promoting it here as there is valuable information in it.

Excellent well summarized article Laura ?
No we’ve not changed SBL policy to require COI. It’s something we very strongly advise but we can not make a requirement. We’ll have to consider it if list-bombing of this magnitude can not be kept in check by list managers.
This incident involved a large number of government addresses belonging to various countries being subscribed to very large numbers of lists in a very short space of time by scripts run by the attacker(s). Most of the lists hit by the attack used COI and therefore only sent confirmation requests and did not subscribe any addresses. The attack undoubtably also hit lists which used Captcha in addition to COI and thus did not even proceed to COI (those list admins deserve some sort of community ‘hi 5’ award, since one can imagine how hard it is to convince one’s management to implement COI let alone put Captcha in front of it).
The issue is the badly-run ‘open’ lists which happily subscribed every address without any consent verification and which now continue as participants in the list-bombing of government addresses. These we are trying to address with SBL listings to prompt resolution by the Senders. As you noticed, most of these particular incident listings are for IPs ending “.0/32” which does not cause any mail issue to the Sender and is deliberately used where we have a good relationship with the Sender and know they will act quickly on the alert.
Steve Linford
Chief Executive
The Spamhaus Project

Efforts are ongoing to help ESPs clean up. Multiple commenters have been sharing data in the comments. If you have data you’d like to share with others, but don’t want to share it publicly please contact me directly.

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Spamhaus Speaks

There’s been a lot of discussion about Spamhaus, spam traps, and blocking. Today, Spamhaus rep Denny Watson posted on the Spamhaus blog about some of the recent large retailer listings. He provides us with some very useful information about how Spamhaus works, and gives 3 case studies of recent listings specifically for transactional messages to traps.
The whole thing is well worth a read, and I strongly encourage you to check out the whole thing.
There are a couple things mentioned in the blog that I think deserve some special attention, though.
Not all spam traps actually accept mail. In fact, in all of the 3 case studies, mail was rejected during the SMTP transaction. This did not stop the senders from continuing to attempt to mail to that address, though. I’ve heard over and over again from senders that the “problem” is that spamtrap addresses actually accept mail. If they would just bounce the messages then there would be no problem. This is clearly untrue when we actually look at the data. All of the companies mentioned are large brick and mortar retailers in the Fortune 200. These are not small or dumb outfits. Still, they have massive problems in their mail programs that mean they continue to send to addresses that bounce and have always bounced.
Listings require multiple hits and ongoing evidence of problems. None of the retailers mentioned in the case studies had a single trap hit. No, they had ongoing and repeated trap hits even after mail was rejected. Another thing senders tell me is that it’s unfair that they’re listed because of “one mistake” or “one trap hit.” The reality is a little different, though. These retailers are listed because they have horrible data hygiene and continually mail to addresses that simply don’t exist. If these retailers were to do one-and-out or even three-and-out then they wouldn’t be listed on the SBL. Denny even says that in the blog post.

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Spamhaus under major dDOS

Late last night I, and a number of other folks, received mail from Spamhaus informing us of a major denial of service attack against their servers. The attack is so bad that the website and main mailserver is currently offline.
DNS services, including rsync and the mirrors, are up and running.
Spamhaus is working to bring the mailserver and website back up, and are hoping to have it up later today.
If there are any critical or particularly urgent SBL issues today, contact your ESP delivery team. The folks who were contacted do have an email address for urgent issues. This is not an address for routine queries, however, and most listees are going to have to wait until normal services are restored to have their listing addressed.
If there is something particularly urgent and your ESP or delivery team does not have a contact address, you can contact me an I can see what I can do.
UPDATE: Most of the IPs people have sent me are actually XBL/CBL listings. But right now the CBL webserver is responding slowly due to the DOS.
If you want to look up a listing without using the Spamhaus website you can use the “host” or “dig” command line tools. To do this reverse the digits in the IP address and append zen.spamhaus.org on the end.
So for the IP 10.11.12.13 you would query 13.12.11.10.zen.spamhaus.org

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