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Why Foldering Adds Very Little Security

I keep hearing stories of people using "foldering" for covert communications. Foldering is the process of composing a message for another party, but instead of sending it as an email, you leave it in the Drafts folder. The other party then logs in to the same email account and reads the message; they can then reply via the same technique. Foldering has been used for a long time, most famously by then-CIA director David Petraeus and his biographer/lover Paula Broadwell. Why is foldering used? more

GDPR PII Time-Bomb? Kill it With Fire!

Hi! My name is spamfighter. I investigate spam and phish in a post-GDPR dystopia. Recently, I invented Fire, to save you millions of €uros. One day, my Boss suggested I automate some of my processes. I, for one, welcome our Robot Overlords (and a happy boss), but I can be exacting about the tools I use. Perhaps not to the degree of the infamous Van Halen 'no brown M&M's' contractual clause but I have no patience for poorly-designed software, and truly dislike typing when... more

Why I Want a .PAYPAL New gTLD

I use Paypal, and I am quite satisfied with how it helps me with my business: it is still a little hard to use, and I don't use all functions of the tool, but it is not so expensive, it is fast and efficient, and Paypal does not send so many emails. In one word, Paypal rocks... The only problem that I have with Paypal is the number of fake emails that I receive. Of course, I easily identify them as they come in and luckily, G Suite (Gmail) does an excellent job at blocking all spam and phishing. more

I Never Signed Up for This! Privacy Implications of Email Tracking

What happens when you open an email and allow it to display embedded images and pixels? You may expect the sender to learn that you've read the email, and which device you used to read it. But in a new paper we find that privacy risks of email tracking extend far beyond senders knowing when emails are viewed. Opening an email can trigger requests to tens of third parties, and many of these requests contain your email address. more

Universal Acceptance of New Top-Level Domains Reloaded

One challenge for all new top-level domains (TLDs) is the so-called Universal Acceptance. Universal Acceptance is a phenomenon as old as TLDs exist and may strike at many occasions... The effect when universal acceptance hits you is that you cannot send or receive email, get error messages or even worse when it looks like everything works but it does not and you do not even get a notification. more

One-Click Unsubscription

Unsubscribing from mailing lists is hard. How many times have you seen a message "please remove me from this list," followed by two or three more pointing out that the instructions are in the footer of every message, followed by three or four more asking people to not send their replies to the whole list (all sent to the whole list, of course,) perhaps with a final message by the list manager saying she's dealt with it? more

The Kindness of Strangers, or Not

A few days ago I was startled to get an anti-spam challenge from an Earthlink user, to whom I had not written. Challenges are a WKBA (well known bad idea) which I thought had been stamped out, but apparently not. The plan of challenges seems simple enough; they demand that the sender does something to prove he's human that a spammer is unlikely to do. more

What is Anti-Spam?

There's a lot of argument as to which "anti-spam" techniques are legitimately so called. In this article, I'd like to consider what constitutes an anti-spam technique in an ideal sense, then consider the various practiced approaches to spam mitigation in that light, drawing conclusions as to how we should frame the "anti-spam" discussion. ...For the purposes of this discussion, let "spam" refer to "unsolicited bulk email". Not everyone agrees on this definition, but it's by far the most widely accepted, and without a working definition we won't be able to define "anti-spam"... more

Logjam, Openssl and Email Deliverability

RHEL6/Centos6 (and presumably RHEL7/Centos7) machines with the latest openssl packages now refuse SSL connections with DH keys shorter than 768 bits. Consider RHEL6 sendmail operating as a client, sending mail out to a target server. If the target server advertises STARTTLS, sendmail will try to negotiate a secure connection. This negotiation uses openssl, which will now refuse to connect to mail servers that have 512 bit DH keys. The maillog will contain entries with "reject=403 4.7.0 TLS handshake failed". more

The Cycle of E-Mail Security

Stepping back from the DMARC arguments, it occurs to me that there is a predictable cycle with every new e-mail security technology... Someone invents a new way to make e-mail more secure, call it SPF or DKIM or DMARC or (this month's mini-fiasco) PGP in DANE. Each scheme has a model of the way that mail works. For some subset of e-mail, the model works great, for other mail it works less great. more

End-to-End Email Encryption - This Time For Sure?

Phil Zimmerman's Pretty Good Privacy (PGP) and its offspring have been encrypting and decrypting email for almost 25 years -- but require enough knowledge and determination to use them that adoption has never taken off outside the technoscenti. Now initiatives from several quarters aim to fix that -- but will it all "just work," and will end users adopt it even if it does? more

When DNSBLs Go Bad

I have often remarked that any fool can run a DNS-Based Blacklist (DNSBL) and many fools do so. Since approximately nobody uses the incompetently run black lists, they don't matter. Unfortunately, using a DNSBL requires equally little expertise, which becomes a problem when an operator wants to shut down a list. When someone sets up a mail server (which we'll call an MTA for Mail Transfer Agent), one of the tasks is to configure the anti-spam features, which invariably involves using DNSBLs. more

Email Vendors: Time to Build in DMARC

DMARC is extremely useful, yet I've heard some vendors are putting their implementations on hold because of the IETF DMARC working group. You really shouldn't wait though -- it's been in wide use for nearly three years, enterprises are looking at DMARC for B2B traffic, and the working group charter is limited in it's scope for changes. Let's compare this to a similar situation in the past. more

The EFF and Hanlon's Razor

The EFF has just posted a shallower than usual deeplink alleging an "email encryption downgrade attack" by ISPs intent on eavesdropping on their customers. They, along with VPN provider Golden Frog, have additionally complained to the FCC reporting this. Here, they've just noticed something that's common across several hotel / airport wifi networks... more

Yahoo Addresses a Security Problem by Breaking Every Mailing List in the World

DMARC is what one might call an emerging e-mail security scheme. It's emerging pretty fast, since many of the largest mail systems in the world have already implemented it, including Gmail, Hotmail/MSN/Outlook, Comcast, and Yahoo. DMARC lets a domain owner make assertions about mail that has their domain in the address on the 'From:' line. It lets the owner assert that mail will have a DKIM signature with the same domain, or an envelope return (bounce) address in the same domain that will pass SPF validation. more