This month in email: February 2014

After a few months of hiatus, I’m resurrecting the this month in email feature. So what did we talk about in February?
Industry News
There was quite a bit of industry news. M3AAWG was in mid-February and there were actually a few sessions we were allowed to blog about. Gmail announced their new pilot FBL program. Ladar Levinson gave the keynote talking about the Lavabit shutdown and his new darkmail program. Brian Krebs won the Mary Litynski award for his work in investigating online security issues. The 4 major mailbox providers talked about their spam filters and spam filtering philosophy.
February was also the month where different companies evaluated their success or failure of products. LinkedIn announced the shutdown of their Intro product and Facebook announced the shutdown of their Facebook.com email service.
Security Issues
Cloudmark published their 2013 report on the Global Spam Threat and we discovered that the massive Target breach started through phishing. I also noticed a serious uptick in the amount of phishing mails in my own mailbox. There is  new round of denial of service attacks using NTP amplification. We provided information on how to secure your NTP servers.
Address Collection
The Hip Hop group De La Soul released their entire catalog for free, online, using a confirmed opt-in email process. On the flip side, the M3AAWG hotel required anyone logging into the wifi network to give an email address and agree to receive marketing mail. We also discovered that some political mailing lists were being used in ways the politicians and recipients didn’t expect.
Email Practices
I talked about how to go about contacting an ISP that doesn’t have a postmaster page or a published method of contact. Much of that information is actually relevant for contacting ISPs that do have a contact method, too. Finally, I talked about how ISPs measure engagement and how that’s significantly different from how ESPs think it is.
 

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I posted an analysis from the ISC yesterday. They had some useful information about the attack and about what everyone should be doing to stop from contributing to future attacks (close your open DNS resolver). The nice thing about this article is that it looked at the attack from the point of view of network health and security.
Today another article was published in TechWeekEurope that said many of the same things that the ISC article did about the size and impact of the attacks.
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ISPs speak at M3AAWG

Last week at M3AAWG representatives from AOL, Yahoo, Gmail and Outlook spoke about their anti-spam technologies and what the organizations were looking for in email.
This session was question and answers, with the moderator asking the majority of the questions. These answers are paraphrased from my notes or the MAAWG twitter stream from the session.
What are your biggest frustrations?
AOL: When senders complain they can’t get mail in and we go look at their stats and complaints are high. Users just don’t love that mail. If complaints are high look at what you may have done differently, content does have an effect on complaints.
Outlook: When we tightened down filters 8 years ago we had to do it. Half of the mail in our users inbox was spam and we were losing a steady number of customers. The filter changes disrupted a lot of senders and caused a lot of pain. But these days only 0.5% of mail in the inbox is spam.  Things happen so fast, though, that the stress can frustrate the team.
Gmail: Good senders do email badly sometimes and their mail gets bulked. Senders have to get the basic email hygiene practices right. Love your users and they’ll love you back.
What’s your philosophy and approach towards mail?
AOL: There is a balance that needs to be struck between good and bad mail. The postmaster team reminds the blocking team that not all mail is bad or malicious. They are the sender advocates inside AOL. But the blocking team deals with so much bad mail, they sometimes forget that some mail is good.
Yahoo: User experience. The user always comes first. We strive to protect them from malicious mail and provide them with the emails they want to see. Everything else is secondary.
Gmail: The faster we stop spam the less spam that gets sent overall. We have highly adaptive filters that can react extremely quickly to spam. This frustrates the spammers and they will give up.
Outlook: The core customer is the mailbox user and they are a priority. We think we have most of the hardcore spam under control, and now we’re focused on personalizing the inbox for each user. Everyone online should hold partners accountable and they should expect to be held accountable in turn. This isn’t just a sender / ESP thing, ISPs block each other if there are spam problems.
What are some of your most outrageous requests?
We’ve been threatened with lawsuits because senders just don’t want to do the work to fix things. Some senders try to extort us. Other senders go to the advertising execs and get the execs to yell at the filtering team.
Coming to MAAWG and getting cornered to talk about a particular sender problem. Some senders have even offered money just to get mail to the spam folder.
Senders who escalate through the wrong channels. We spent all this money and time creating channels where you can contact us, and then senders don’t use them.
Confusing business interests with product interests. These are separate things and we can’t change the product to match your business interest.
What are your recommendations for changing behaviors?
Outlook: We provide lots of tools to let you see what your recipients are doing. USE THE TOOLS. Pay attention to your recipient interaction with mail. Re-opt-in recipients periodically. Think about that mail that is never opened. Monitor how people interact with your mail. When you have a problem, use our webpages and our forms. Standard delivery problems have a play book. We’re going to follow that playbook and if you try to get personal attention it’s going to slow things down. If there’s a process problem, we are reachable and can handle them personally. But use the postmaster page for most things.
Gmail: Get your hygiene right. If you get your hygiene right, deliverability just works. If you’re seeing blocking, that’s because users are marking your mail as spam. Pay attention to what the major receivers publish on their postmaster pages. Don’t just follow the letter of the law, follow the spirit as well. Our responsibility, as an ISP, is to detect spam and not spam. Good mailers make that harder on us because they do thinks that look like spammers. This doesn’t get spammer mail in more, it gets legitimate mail in less. Use a real opt-in system, don’t just rely on an implied opt-in because someone made a purchase or something.
Yahoo: ESPs are pretty good about screening their customers, so pay attention to what your ESPs are saying. Send mail people want. Verify that the email addresses given to you actually belong to people who want your mail. Have better sender practices.
What do you think about seed accounts?
The panel wasn’t very happy about the use of seed accounts. Seeds are not that useful any longer, as the ISPs move to more and more personalized delivery. Too much time and too many cycles are used debugging seed accounts. The dynamic delivery works all ways.
When things go wrong what should we do?
AOL: Open a ticket. We know we’ve been lax recently, but have worked out of our backlog and are caught up to date. Using the ticketing system also justifies us getting more headcount and makes everyone’s experience better. Also, don’t continue what you’re doing. Pausing sending while you’re troubleshooting the issue. We won’t adjust a rep for you, but we may be able to help you.
Gmail: Do not jump the gun and open a ticket on the first mail to the spam folder. Our filters are so dynamic, they update every few minutes in some cases. Be sure there is a problem. If you are sure you’re following the spirit and letter of the sender guidelines you can submit a ticket. We don’t respond to tickets, but we work every single one. When you’re opening a ticket provide complete information and full headers, and use the headers from your own email address not headers from a seed account. Give us a clear and concise description of the problem. Also, use the gmail product forum, it is monitored by employees and it’s our preferred way of getting information to the anti-abuse team. Common issues lots of senders are having will get addressed faster.
Outlook: Dig in and do your own troubleshooting, don’t rely on us to tell you what to fix. The support teams don’t have a lot of resources so use our public information. If you make our job harder, then it takes longer to get things done. But tell us what changes you’ve made. If you’ve fixed something, and tell us, our process is different than if you’re just asking for a delisting or asking for information. When you’ve fixed things we will respond faster.
How fast should users expect filters to respond after making changes?
Filters update continually so they should start seeing delivery changes almost immediately. What we find is people tell us they’ve made changes, but they haven’t made enough or made the right ones. If the filters don’t update, then you’ve not fixed the problem.

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More denial of service attacks

There are quite a lot of NTP-amplified denial of service attacks going around at the moment targeting tech and ecommerce companies, including some in the email space.
What does NTP-amplifed mean? NTP is “Network Time Protocol” – it allows computers to set their clocks based on an accurate source, and keep them accurate. It’s very widely used – OS X and Windows desktops typically use it by default, and most servers should have it running.
NTP is a UDP based service, like DNS, one that works by sending a packet to a server and the server sending a packet back rather than opening a persistent connection to the server as TCP based services (e.g. SMTP, HTTP, …) do. That simpler protocol means that it’s easy for me to send a request to an NTP server with a false source address, claiming I’m someone else – and the NTP server will send it’s reply back to that fake source address rather than to me. So if I want to DoS someone by flooding their network with packets I can send NTP requests to a public NTP server claiming to be the victims server. The NTP server will send the replies back to the victim – and it’ll be almost impossible for the victim, or the NTP server, to trace where I’m sending those request packets from.
As a malicious attacker that already sounds good – but it gets better. The size of a reply is often bigger than the size of a request, sometimes a lot bigger. If I choose the request I make carefully I can easily make sure the reply is at least an order of magnitude bigger than the request. So for every megabit of forged requests I sent to NTP servers, the victim might see at least 10 times that hitting their servers. That’s amplification.
What can you do about it? If you’re running NTP servers that will respond to requests from the general Internet, you ideally need to lock those down so that they’ll only respond to requests from your own clients. You can use the instructions and information at the open NTP project to check to see if you’re running open NTP servers and use the templates provided by Project Cymru as a basis to secure your NTP servers and appliances.
What can you do to prepare for this sort of attack? Have monitoring in place, so that you’re notified if there are large volumes of unexpected traffic. Overprovision your bandwidth, if possible, to give you more time to react. Block “large” (>90 bytes for IPv4, >110 for IPv6) UDP packets with a source or destination port of 123 as far upstream as possible, and all UDP packets that have both a source port of 123 and a destination port of 80 or 25 – this shouldn’t affect legitimate use of NTP by your users. Consider having your production servers use NTP servers operated by you, rather than public NTP servers – that way, if they’re targeted you can block any traffic that looks like NTP to them without affecting their time synchronization. Research DoS mitigation providers – different providers have different strengths and cost structures, and they can be much more reasonably priced if you talk to them before an attack rather than during one.
What if you’re targeted by this sort of attack? If you’re not a sysadmin, stay out of your sysadmins way and make sure there’s coffee, food and a quiet place without interruptions available. If you are a sysadmin, talk to your upstream NOC. They’re in a much better place, in information, resources and knowledge, than you to help mitigate. Reach out to your peers who are also being attacked and offer to share information. Look at Cisco’s mitigation advice. The attack will probably target your publicly visible website. If so, consider moving that to another network (or behind a commercial DoS mitigation provider) so that your production servers and customer portal web presence isn’t impacted.
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