When spam filters fail

Spam filters aren’t perfect. They sometimes catch mail they shouldn’t, although it happens less than some people think. They sometimes fail to catch mail they should.
One of the reason filters fail to catch mail they should is because some spammers invest a lot of time and energy in figuring out how to get past the filters. This is nothing new, 8 or 9 years ago I was in negotiations with a potential client. They told me they had people who started working at 5pm eastern. Their entire job was to craft mail that would get through Hotmail’s filters that day. As soon as they found a particular message that made it to the inbox, they’d blast to their list until the filters caught up. When the filters caught up, they’d start testing again. This went on all night or until the full list was sent.
Since then I’ve heard of a lot of other filter bypass techniques. Some spammers set up thousands of probe accounts at ISPs and would go through and “not spam” their mail to fool the filters (ISPs adapted). Some spammers set up thousands of IPs and rotate through them (ISPs adapted). Some spammers register new domains for every send (ISPs adapted). Some spammers used botnets (ISPs adapted)
I’m sure, even now, there are spammers who are creating new techniques to get through filters. And the ISPs will adapt.

Thoughts on Hotmail filtering
Recipients need to be able to unsubscribe

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You can't always get what you want

It’s a problem anyone who has done any delivery work has faced. There’s a client who is having blocklist problems or ISP delivery problems and they won’t pay any attention to what you say. They insist that you talk to the blocklist or the ISP or hand over contacts directly so they can “dialog with” someone internally. They don’t like what they’re hearing, and they hope that the answer will be different if they find a new person to talk to.
The reality is many of the people at ISPs and blocklists don’t want to talk to these types of senders. They may answer a friendly question from someone they know and trust, but sometimes not even then.
Some very large ISPs and major blocklists don’t even take sender questions. They won’t communicate with anyone about any delivery issues.
I’ve had to tell more than a few clients recently that various ISPs and blocklists weren’t interested in helping those clients with their delivery problems. There are two classes of reactions I get from clients. Some clients focus on moving forward. “OK, now what? How can we identify the issue, what data do we have and how can we figure out what the problem is?”
Other clients continue to look for ways to talk to whomever is blocking their mail. They’re convinced if they can just “explain their business model” or be told what they’re doing wrong, that all their delivery problems will magically disappear.
Needless to say those clients who focus on moving forward and looking at the information they do have have much better success resolving their delivery problems. What many senders don’t understand is the wealth of data they have that will help them resolve the issue. And even if they know it’s buried in their files, they don’t always know where to start looking or even what they’re looking for.
But that is, of course, why you hire someone like me who understands spamfiltering and email. I help senders understand how email filters work and identify what parts of their programs are likely to be responsible for delivery issues. I often find the most valuable service I provide to clients is a fresh set of eyes that can see the forest. With my help, they manage to stop obsessing unproductively about one particular symptom and focus on the underlying problems.
Senders who think the holy grail of problem resolution is speaking to the right person at an ISP or blocklist generally are disappointed, even when they hire someone who knows all the right people at the ISPs.  They can’t always get what they want. But I can often help them get what they need.
 
 
 

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Abuse it and lose it

Last week I blogged about the changes at ISPs that make “ISP Relations” harder for many senders. But it’s not just ISPs that are making it a little more difficult to get answers to questions, some spam filtering companies are pulling back on offering support to senders.
For instance, Cloudmark sent out an email to some ESPs late last week informing them that Cloudmark was changing their sender support policies. It’s not that they’re overwhelmed with delisting requests, but rather that many ESPs are asking for specific data about why the mail was blocked. In December, Spamcop informed some ESPs that they would stop providing data to those ESPs about specific blocks and spam trap hits.
These decisions make it harder for ESPs to identify specific customers and lists causing them to get blocked. But I understand why the filtering companies have had to take such a radical step.
Support for senders by filtering companies is a side issue. Their customers are the users of the filtering service and support teams are there to help paying customers. Many of the folks at the filtering companies are good people, though, and they’re willing to help blocked senders and ESPs to figure out the problem.
For them, providing information that helps a company clean up is a win. If an ESP has a spamming customer and the information from the filtering company is helping the ESP force the customer to stop spamming that’s a win and that’s why the filtering companies started providing that data to ESPs.
Unfortunately, there are people who take advantage of the filtering companies. I have dozens of stories about how people are taking advantage of the filtering companies. I won’t share specifics, but the summary is that some people and ESPs ask for the same data over and over and over again. The filtering company rep, in an effort to be helpful and improve the overall email ecosystem, answers their questions and sends the data. In some cases, the ESP acts on the data, the mail stream improves and everyone is happy (except maybe the spammer). In other cases, though, the filtering company sees no change in the mail stream. All the filtering company person gets is yet another request for the same data they sent yesterday.
Repetition is tedious. Repetition is frustrating. Repetition is disheartening. Repetition is annoying.
What we’re seeing from both Spamcop and Cloudmark is the logical result from their reps being tired of dealing with ESPs that aren’t visibly fixing their customer spam problems. Both companies are sending some ESPs to the back of the line when it comes to handling information requests, whether or not those ESPs have actually been part of the problem previously.
The Cloudmark letter makes it clear what they’re frustrated about.

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Botnets and viruses and phishing, oh my!

MessageLabs released their monthly report on email threats yesterday. Many media outlets picked up and reported that 41% of spam was from a the Rustock botnet.
Other highlights from the report include:

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