TagDKIM

About that DMARC "exploit"

A security researcher has identified a rendering flaw that allows for “perfect” phishing emails. From his website: Mailsploit is a collection of bugs in email clients that allow effective sender spoofing and code injection attacks. The spoofing is not detected by Mail Transfer Agents (MTA) aka email servers, therefore circumventing spoofing protection mechanisms such as DMARC...

The feds are deploying DMARC

The US National Cybersecurity Assessments & Technical Services Team have issued a mandate on web and email security, including TLS+HSTS for web servers, and STARTTLS+SPF+DKIM+DMARC for email. It’s … pretty decent for a brief, public requirements doc. It’s compatible with a prudent rollout of email authentication. Set up a centralized reporting repository for DMARC failure...

Are they using DKIM?

It’s easy to tell if a domain is using SPF – look up the TXT record for the domain and see if any of them begin with “v=spf1”. If one does, they’re using SPF. If none do, they’re not. (If more than one does? They’re publishing invalid SPF.) AOL are publishing SPF. Geocities aren’t. For DKIM it’s harder, as a DKIM key isn’t published at a...

The philosophy of DMARC

We know that legitimate email sent with valid SPF and a DKIM signature often breaks in transit. SPF will fail any time mail is forwarded – via a mailing list, a forwarding service used by the recipient, or just ad-hoc forwarding. DKIM will fail any time the message is modified in transit. That can be obviously visible changes, such as a mailing list tagging a subject header or adding a...

Tools!

I just added a DMARC validation tool over on tools.wordtothewise.com. You can give it a domain – such as ebay.com – and it will fetch the DMARC record, then explain and validate it. Or you can paste the DMARC record you’re planning to publish into it,  to validate it before you go live. If you’ve not seen our tools page before, take a look. As well as DMARC we have a DKIM...

December 2016: The Month in Email

Happy New Year! We’re looking forward to some interesting new projects this year, both for our clients and for Word to the Wise. Stay tuned! December was a slow month for blogging, with everything going on. But we’re back on the horse now and ready to blog for 2017. List and subscription management continue to be hot topics, especially in the wake of the listbombing attacks earlier this...

DKIM Canonicalization – or – why Microsoft breaks your mail

One of these things is just like the other Canonicalization is about comparing things to see if they’re the same. Sometimes you want to do a “fuzzy” comparison, to see if two things are interchangeable for your purposes, even if they’re not exactly identical. As a concrete example, these two email addresses: (Steve) steve@wordtothewise.com “Also Steve”...

Gmail showing authentication results to endusers

A bit of older news, but worth a blog post. Early in August, Gmail announced changes to the inbox on both the web interface and the android client. They will be pushing authentication results into the interface, so end users can see which emails are authenticated. These are not deliverability changes, the presence or absence of authentication will not affect inbox delivery. And the gmail Gmail...

Don't just follow the HOWTO

There are so many moving parts to ensure good email deliverability. Email marketers need to know marketing, they need to know email and they need to know design. The technical bits of email can be a challenge to learn, and many folks who write tutorials and How-Tos write them for a different audience than marketers. One of the things I’m trying to do is demystify the technical end of email...

A DKIM primer resurrected

I was looking for some references today back in old blog posts. This means I discover some old links are dead, blog posts are gone or moved, and information is lost. In this case it’s a post by J.D. Falk on deliverability.com. The link is dead (it looks like the whole website is dead), but I found a copy of his post and am reproducing it here. I don’t have permission, because I...

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