Wacky Weekend: The '.secure' gTLD

Fri Jun 1 01:16:21 UTC 2012

On May 31, 2012, at 5:43 PM, Grant Ridder wrote:

> I think this is an interesting concept, but i don't know how well it will
> hold up in the long run.  All the initial verification and continuous
> scanning will no doubtingly give the .secure TLD a high cost relative to
> other TLD's.

not necessarily. It can be done with a laptop that does "dig" and sends email to the place.

What will drive the price up is the lawsuits that come out of the woodwork when they start trying to enforce their provisions. "What? I have already printed my letterhead! What do you mean my busted DKIM service is a problem?"

BTW, getting DKIM on stuff isn't the issue. I'm already getting spam with DKIM headers in it. It's getting the policy in place that if a domain is known to be using DKIM, to drop traffic from it that isn't signed or for which the signature fails.

You may find the following exchange with my military son, whose buddies apparently call me "skynet", amusing...

Begin forwarded message:

> From: Fred Baker <fred at cisco.com>
> Date: May 9, 2012 12:55:40 PM PDT
> To: Colin Baker <...>
> Subject: Re: skynet
> 
> On May 9, 2012, at 2:14 PM, Colin Baker wrote:
>> so my friends and i have taken to calling you 'Skynet' since you
>> invented the internet and have full access to all technological
>> secrets...
>> 
>> A question came up last night regarding phishing attempts.  When we
>> call our banks or other companies, we have to identify as the customer
>> by giving specific info such as mother's maiden name, password, last
>> 4, etc.  That is so the company knows that this is us and not an
>> identify thief.
>> 
>> Why dont companies have to do the same thing with us?  I could get a
>> random call from someone claiming to be Wells Fargo, but they dont
>> have to do anything like 'the wells fargo secret code is 117 and the
>> authentication for me to call about your account is 7G.'  would it
>> make sense to have that sort of two-way authentication?
>> 
>> We thought you might know, since your hands are in every realm of
>> current business practices, technology, and you read the encyclopedia
>> as a kid.
> 
> Well, show this to your buddies.
> 
> If you're using Apple Mail, right now, go to the "View" bar, go down to "Message", and from there to "Raw Source". An email message contains two parts - one that is the email itself, and one (called the "envelope") that contains information used in sending the message around. There will be several lines that start with "Received:"; they tell you that the message was received by a specific Mail Transfer Agent (an application running on a computer) at a certain time; if there are several of them, you can infer that the MTA that received it sent it to the next, and if you're looking for delays in mail transfer, a large difference in time is a smoking weapon saying where that delay was.
> 
> Also in the envelope, you may find a datum that looks like:
> 
>> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple;
>> d=cisco.com; i=tli at cisco.com; l=319; q=dns/txt;
>> s=iport; t=1336587580; x=1337797180;
>> h=subject:mime-version:from:in-reply-to:date:cc:
>>  content-transfer-encoding:message-id:references:to;
>> bh=cXlHIR7jgb7lDsoGWEAx6MS6AJ7zJwnnwkO+N7lsBqs=;
>> b=gks8REH7Yho0kcjPt/+H8FJMmi0qF/tZ/mpARWFevTiObT64ZaXog3+k
>>  tDKdaPOAYQYJ8OoJfT/ynOGdtOnN87adlM0lUoDgY5s7bg6juBnaSESG0
>>  UMo18OTQiwuXzV94LNzNSl3lsH++1tfzbsNJe1p+TzjGtBljFoQgMZu4l
>>  c=;
> 
> That particular one is from an email sent to me by a colleague named Tony Li <tli at cisco.com>, who is a Cisco employee. It gives you proof that the message originated from Cisco, and in this case, that Cisco believes that it was originated by Tony Li.
> 
> I'll bet you find a similar thing in this very note.
> 
> "DKIM" stands for "Domain Keys Identified Mail", and is used by Google, Yahoo, and Cisco among others. Here's the DKIM Information Element from the email you sent me:
> 
>> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
>>       d=gmail.com; s=20120113;
>>       h=mime-version:date:message-id:subject:from:to:content-type;
>>       bh=+PAULPy6MwBt3TU1am4I5yRRvfudEeK0k2nzWGCD6kY=;
>>       b=aKMwdM9q/Jh72pJ51i3Kyumy6wIMk6osgAfCyukFh2ATgiy3yWuu5oam4/DgRvo81+
>>        OD0xeYqSyTx2Z2qjUxHtz9kl5nxCkNWlePbOjefog0gfPH1nKN/Kw/562k7OFvl3WeXd
>>        hOIfpNOZb+W5wBIavFg9HKLvr8oDCcNNNkAx0c4WlynMNodcpQVkFchsYDFfV0x5jNme
>>        st/+XLCNmjE1h73/WGmRn3AVJ7WaHKWWdW8PDKw2p1HLnrN8l1FCDeWDX6dMHtABSLuH
>>        C5ScenHkhgPDcAyDdjSmVqEPmuaUB4GU7BaNRqwsUMjcvJZxYuOETux05pBYY2HpRYTC
>>        D6yQ==
> 
> The theory is that if someone (your MTA, not your computer) receives such an information element, it can apply a policy. The policy might say 
> 
> - "I don't think that domain <> implements DKIM, so I'll just accept the message", or 
> - "I think it does, but this email doesn't have one, so obviously this isn't from that domain and therefore is bogus; I'll drop it", or 
> - "I think it does, and this email has one, but the signature is bogus; I'll drop it", or 
> - "I think it does, and this email has one that checks out, so I'll deliver it to Lt Baker".
> 
> There is another approach, called Secure MIME or S/MIME. Your military mail system uses it. It puts a signature on every email that you send, so we can definitively say that you personally sent it, and if we get an email from a military address that either has no signature or the signature is invalid, we can drop it. S/MIME has an additional capability - it can encrypt the mail, and it can even encrypt it in a way that only the person you sent it to can read it.
> 
> Policy.
> 
> What if nobody implements the policy? We all put signatures on our mail, but nobody checks them?
> 
> Phishing. That's what happens.
> 
> We're trying to make the network self-aware. We need to make the humans self-aware before we can do that.

> Oh, I should have also said something else.
> 
> In addition, we are capable of authenticating a user that sends an email. Again assuming that you're using Apple Mail, go to the "Mail" header on the upper bar, to "Preferences", to "Accounts", to your outgoing mail server (SMTP), to "Edit SMTP Server List", to "Advanced". You'll see there that you can select a different port for mail, and that you have the option of using the Secure Sockets Layer (SSL) between you and your first MTA - your SMTP mail server. If that is configured, the server can say it knows for sure that the mail originated with you, and can therefore apply the DKIM signature.
> 
> I mentioned that I'm getting spam from Austin's YAHOO account; I wonder if you are. YAHOO uses DKIM as well, but whoever is really sending it is tricking YAHOO into believing the email is from Austin, which I suspect means that either YAHOO isn't using SSL or someone got Austin's credentials. 
> 
> There are two weak links. People using the tools, and network administrators using the tools. If they are actually used, as far as we know they work. They are often not or only partially used.