What’s So Tricky about DOD’s PKI That It Needs to Expose Thousands of Service Members?

Motherboard decided to call out DOD for not using STARTTLS to encrypt the transiting email of much of DOD’s emails.

[A]s encryption spreads to government sites, it hasn’t reached government emails yet. Most of the military as well as the intelligence community do not use encryption to protect emails travelling across the internet.


In fact, according to an online testing tool, among the military only the Air Force encrypts emails in transit using a technology called STARTTLS, which has existed since 2002. Other branches of the Pentagon, including the Army, the Navy, the Defense Security Service, and DARPA, don’t use it. Even the standard military email provider mail.mil, doesn’t support STARTTLS.


In a statement emailed to Motherboard, a spokesperson for the Defense Information Systems Agency (DISA), the Pentagon’s branch that oversees email and other technologies, said the DISA’s DOD Enterprise Email (DEE) does not support STARTTLS.

This part of the story is bad enough. I take it to mean that as people stationed overseas email home, their email — and therefore significant hints about deployment — would be accessible to anyone who wanted to steal them in transit. While more sensitive discussions would be secure, there would be plenty accessible to Russia or China or technically savvy terrorists to make stealing the email worthwhile.

But I’m just as struck by DOD’s excuse.

“STARTTLS is an extension for the Post Office Protocol 3 and Internet Message Access protocols, which rely on username and password for system access,” the spokesperson wrote. “To remain compliant with DOD PKI policy, DEE does not support the use of username and password to grant access, and does not leverage either protocol.”

First of all, this doesn’t make any sense. The Public Key Infrastructure system, which controls access to DOD networks, should be totally separate from the email system.

Worse still: we know a little bit about what — and when — DOD implemented its PKI, because it came up in Congressional hearings in the wake of the Chelsea Manning leaks. Here’s what DOD’s witnesses explained back in 2011.

One of the major contributing factors in the WikiLeaks incident was the large amount of data that was accessible with little or no access controls. Broad access to information can be combined with access controls in order to mitigate this vulnerability. While there are many sites on SIPRNet that do have access controls, these are mostly password-based and therefore do not scale well. The administration of thousands of passwords is labor intensive and it is difficult to determine who should (and should not) have access.

DoD has begun to issue a Public Key Infrastructure (PKI)-based identity credential on a hardened smart card. This is very similar to the Common Access Card (CAC) we use on our unclassified network. We will complete issuing 500,000 cards to our SIPRNet users, along with card readers and software, by the end of 2012. This will provide very strong identification of the person accessing the network and requesting data. It will both deter bad behavior and require absolute identification of who is accessing data and managing that access.

In conjunction with this, all DoD organizations will configure their SIPRNetbased systems to use the PKI credentials to strongly authenticate end-users who are accessing information in the system. This provides the link between end users and the specific data they can access – not just network access. This should, based on our experience on the unclassified networks, be straightforward.

DoD’s goal is that by 2013, following completion of credential issuance, all SIPRNet users will log into their local computers with their SIPRNet PKI/smart card credential. This will mirror what we already do on the unclassified networks with CACs.

Remember, this describes the log-in process to DOD’s classified network, generally, not to email.

The point is, though, that in response to an internal leaker, DOD only rolled out the kind of network controls most businesses have on its Secret (not Top Secret) network in 2011. Even if there were something about that roll-out that did impact email, what DOD would have you believe that as late as 2011, they made decisions that resulted in keeping email insecure in transit.

7 replies
  1. jerryy says:

    Someone at the DOD is spewing out utter bs.
    The starttls command (which means – start transport layer socket – a type of sort of secure encrpyted chatting between mail delivery servers) is used by the email delivery servers between each other. It has ABSOLUTELY nothing to do with using PKI services or username / password access.
    They are lying.

  2. Anon says:

    While I agree that it makes no logical sense that it should operate that way I would not at all be surprised to find out that it does.
    Consider the Pentagon’s existing procurement process and it’s most recent shining examples of the F-35 non-fighter and the Littoral Combat/Patrol/Offshore Prison ship. If these examples demonstrate anything it is that they do not select for the simplest, most robust, designs. Nor are they particularly good at quality control.
    Therefore I refuse to rule out the possibility that whatever billion-dollar boondoggle they do have does require emails in the clear to handle access.

  3. Saul Tannenbaum says:

    I could go deep into the weeds here, but I’ll try not to.

    DOD PKI uses X.509 certificates. Typically, in X.509 implementations, you don’t actually directly log into email servers. Instead, authentication is done by an external, trusted directory server which examines the user’s X.509 certificate for validity and reports back to the email server. DEE looks like its Microsoft Exchange, so that external authentication is almost certainly Active Directory.

    At that point, the client has presented a valid encryption certificate, the server has its encyption certificate, and it can encrypt everything with those certs, outside of the more general STARTTLS mechanism.

    So, they’re literally correct when they say they don’t leverage username and password, they have certificates. And, if you’re doing end-user certificates, you want it to work with everything and managing exactly one credential per person.

    It’s true that most out-of-the-box open source solutions don’t work like this at all, and that, in those contexts, not supporting STARTTLS is malpractice. But, if you can force everybody into a full-bore Microsoft environment, as DOD seems to have done, you can rely on a whole ecosystem of encryption that can make you secure without STARTTLS.

    • jerryy says:

      What you are referring to is related to the end user logging in to check their email, such as someone using Outlook or Thunderbird in the ‘group’ environment. While that type of email delivery device should be secured and can use tls just as browsers can use tls for secure pages, it is different than the mta service that is being discussed.
      MTAs (mail transfer agents) are the daemons that are at the heart of the Internet email system, such as Yahoo! contacting Google to turn over a bunch of email from Yahoo! senders to GMail receivers, or inside a large private network with internal nodes.
      The end user never interacts with a mta, admins seldom do other than to check to make sure things are running smoothly.
      MTAs are configured as to how to implement starttls so they talk or not to other MTAs and send on the email or not depending on how the receiving MTA implements starttls. One option that has been there from the get-go is to not transfer email if the receiver does not use the secure transfer method.

      • Saul Tannenbaum says:

        I was responding to Marcy’s question about the DOD statement which referenced POP and IMAP, not SMTP, and was explaining how that statement could be, strictly speaking, accurate.

        It’s certainly true that the Motherboard article seems to be talking about SMTP and MTAs (though it never actually says that). From that perspective, the DOD statement was a non-sequitur.

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