Comment This is one of the major problems with DKIM et.al. (Score 4, Informative) 17
For those who don't deal with email infrastructure: there are several technologies (DKIM, SPF, etc.) that have been deployed in attempts to stop email forgery. Each works slightly differently, but the overall concept is that a receiving email server can check that a sending email server is authorized to send messages from the message sender's domain (e.g., "this message presented by mail3.example.net claims to be from joe@example.com; is mail3.example.net allowed to originate email from example.com?") and that messages are cryptographically signed by the sending domain's email server(s). I'm oversimplifying a lot but that's the general idea.
Worth noting is that tells you nothing about the message, i.e., it's of no value in figuring out if the message is spam or ham. That's because spammers can set up all of this too, and most of them have. It's of no help with the big email providers either: the two biggest sources of spam observed here are Gmail and Outlook, and of course all of those messages pass every one of these checks.
Which brings me to this problem. And that is: if someone gains control of an email account (or an email server) then they can send whatever they want from it until someone notices and shuts it down. And all of those messages will pass all of these checks -- which means that they're highly likely to be accepted by recipient email servers and highly likely to be read by the addressees. And then it gets worse: some of those addressees are using email clients that check message validity and signal it to the user with a green checkmark or the word "verified" or something like that. So even if the message content seems a little sketchy, that might well be enough to convince the person reading it that is IS legitimate...and then bad things happen.
We've spent decades trying to train users to be suspicious of anything that doesn't look right -- with mixed results, of course. But the combination of these technologies and email user interfaces that use them is undoing that training. Users are being conditioned to believe what their email client tells them to believe, and this is going to have dire consequences.
Worth noting is that tells you nothing about the message, i.e., it's of no value in figuring out if the message is spam or ham. That's because spammers can set up all of this too, and most of them have. It's of no help with the big email providers either: the two biggest sources of spam observed here are Gmail and Outlook, and of course all of those messages pass every one of these checks.
Which brings me to this problem. And that is: if someone gains control of an email account (or an email server) then they can send whatever they want from it until someone notices and shuts it down. And all of those messages will pass all of these checks -- which means that they're highly likely to be accepted by recipient email servers and highly likely to be read by the addressees. And then it gets worse: some of those addressees are using email clients that check message validity and signal it to the user with a green checkmark or the word "verified" or something like that. So even if the message content seems a little sketchy, that might well be enough to convince the person reading it that is IS legitimate...and then bad things happen.
We've spent decades trying to train users to be suspicious of anything that doesn't look right -- with mixed results, of course. But the combination of these technologies and email user interfaces that use them is undoing that training. Users are being conditioned to believe what their email client tells them to believe, and this is going to have dire consequences.