Spammers react to Y! DMARC policy

It’s probably only a surprise to people who think DMARC is the silver bullet to fixing email problems, but the spammers who were so abusing yahoo.com have moved on… to ymail.com.
In the rush to deploy their DMARC policy, apparently Yahoo forgot they have hundreds of other domains. Domains that are currently not publishing a DMARC policy. Spammers are now using those domains as the 5322.from address in their emails. The mail isn’t coming through any yahoo.com domain, but came through an IP belonging to Sprint PCS.
ymail_dmarc
This is just one example of how spammers have reacted to the brave new world of p=reject policies by mailbox providers. If only the rest of us could react as quickly and as transparently to the problems imposed by these policy declarations. But changing software to cope with the changes in a way that keeps email useful for end users is a challenge. What is the right way to change mailing lists to compensate for these policy declarations? How can we keep bulk email useful for small groups that aren’t necessarily associated with a “brand”?
The conversation surrounding how we minimize the damage to the ecosystem that p=reject policy imposed hasn’t really happened. I think it is a shame and a failure that people can’t even discuss the implications of this policy. Even now that people have done the firefighting to deal with the immediate problems there still doesn’t seem to be the desire to discuss the longer effect of these changes. Just saying “these are challenges” in certain spaces gets the response “just deal with it.” Well, yes, we are trying to deal with it.
I contend that in order to “just deal with it”, we have to define “IT.” We can’t solve a problem if we can’t define the problem we’re trying to solve. Sadly, it seems legitimate mailers are stuck coping with the fallout, while spammers have moved on and are totally unaffected.
How is this really a win?

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DMARC and organizations

Comcast recently published a statement on DMARC over on their postmaster page. The short version is that Comcast is publishing a DMARC record, but has no current intentions to publish a p=reject policy for Comcast user email. Comcast will be publishing a p=reject for some of their domains that they use exclusively to communicate with customers, like billing notices and security notices.
Comcast does point out that Yahoo! and AOL’s usage of p=reject is “not common usage.”
This is something a lot of people have been arguing loudly about on various mail operations lists and network lists. DMARC is about organizational identity. In fact, I was contacted about my DMARC primer and told that I didn’t mention that it’s not about domains, it’s about organizations.
The way I read the DMARC spec, it is all about organizational identity. The underlying theme being that the domain name is linked to a particular organization and everyone using email at that domain has some official relationship with that organization. I’ve always read the spec mentally replacing organization with corporate brand. This was for brands and organizations that strictly control how their domains are used, who can use those domains and how the mail is sent with those domains.
I never expected any mailbox provider or commercial ISP to publish a p=reject message as it would just break way too much of the way customers use email. And it did break a lot of legitimate and end user uses of email. Many organizations have had to scramble to update mailing list software to avoid bouncing users off the lists. Some of these upgrades have broken mailbox filters, forcing endusers to change how they manage their mailboxes.
Even organizations see challenges with a p=reject message and can have legitimate mail blocked. At M3AAWG 30 in San Francisco I was talking with some folks who have been actively deploying DMARC for organizations. From my point of view anyone who wants to publish a DMARC p=reject should spend at least 6 months monitoring DMARC failures to identify legitimate sources of email. The person I was talking to said he recommends a minimum of 12 months.
This is just an example of how difficult it is to capture all the legitimate sources of emails from a domain and effectively authenticate that mail. For a mailbox provider, I think it’s nearly impossible to capture all the legitimate uses of email and authenticate them.
It remains to be seen if the other mailbox providers imitate Yahoo! and AOL or if they push back against the use of DMARC reject policies at mailbox providers. Whatever the outcome, this is a significant shift in how email is used. And we’re all going to have to deal with the fallout of that.

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Yahoo DMARC articles worth reading

There are a bunch of them and they’re all worth reading.
I have more to say about DMARC, both in terms of advice for senders and list managers affected by this, and in terms of the broader implications of this policy decision. But those articles are going to take me a little longer to write.
How widespread is the problem? Andrew Barrett publishes numbers, pulled from his employer, related to the number of senders using @yahoo.com addresses in their commercial emails. Short version: a low percentage but a lot of users and emails in raw numbers.
What can mailing list managers do? Right now the two answers seem to be stop Yahoo.com addresses from posting or fix your mailing list software. Al has posted how he patched his software to cope, and linked to a post by OnlineGroups.net about how they patched their software.
A number of people are recommending adding an Original Authentication Results header as recommended in the DMARC.org FAQ. I’m looking for more information about how that would work.
For commercial mailers, there doesn’t seem to be that much to do except to not use @yahoo.com address as your header-From address. Yes, this may affect delivery while you’re switching to the new From address, but right now your mail isn’t going to any mailbox provider that implements DMARC checking.
One other thing that commercial mailers and ESPs should be aware of. Depending on your bounce handling processes, this may cause other addresses to bounce off the list. Once the issue of the header-From address is settled, you can reactivate addresses that bounced off the list due to authentication failures since April 4.
 

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Dealing with DMARC for Mail intermediaries

I’ve been getting some mail and calls from folks looking for help on resolving the issue of DMARC bouncing. Some of these calls are from ESPs, but others are from SAAS providers who have users that have signed up with yahoo.com addresses and are now dealing with mail from those users bouncing, even when mail is going back too those users.
None of the solutions are really great, but here are a couple options.
1) Prohibit users users from sending with @yahoo.com header-from addresses. This will be challenging for some companies for all sorts of reasons. I have seen a number of people suggest switching to @hotmail.com or @gmail.com addresses. This only works as long as Gmail and Hotmail/Outlook don’t start publishing p=reject policies. It’s unclear if they’re even considering this at all, but it may happen.
2) Rewrite the header-from address from @yahoo.com to something you control. One thing I’ve been suggesting to customers is set up a specific domain for rewriting, like @yahoo.ESP.com. This domain would need to forward mail back to the @yahoo.com users, which does add another layer of complexity as these addresses will become spam magnets. Thus the forwarding IP should be on a distinct and separate IP, to prevent interference with other systems. Note, too, that any users sending to these reply addresses from a domain protected by DMARC p=reject will bounce.
If you have questions or want to ask specifically about what to do in your setup, I’ve blocked out some time in my schedule next week for companies. If you want more information about this please contact me to for available times, information requirements and pricing.

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