7 ms·

I don't get what's insecure about normal unencrypted email. It's sent over https, isn't it? It's not like I can read your emails unless I break into Google's se

• jcranmer 7y ago
  In modern practice, email is sent over TLS sockets already. Any good email client should prohibit you from using SMTP, POP, or IMAP with TLS, and for the past few years, even the MX-MX transfers in the backend have started to become protected (albeit mostly opportunistically at this point, I believe) with TLS. So the only people who can read email are you, your counterparty, your ESP, and your counterparty's ESP, assuming the email providers are following good practice.
  • Godel_unicode 7y ago
    This is an excellent explanation overall, I do however think that it's important to note that opportunistic STARTTLS is vulnerable to downgrade attacks by mitm. Since this would have to be a mitm of e.g. Gmail it's not trivial by any means, but neither is it completely out of reach (see for example the periodic rerouting of the internet caused by odd BGP advertisements). One further note is that you can know post-hoc if an email was delivered to Gmail via TLS by the presence or absence of a red lock in the Gmail app or web UI.
    • bigiain 7y ago
      > STARTTLS is vulnerable to downgrade attacks by mitm. Not only that, but intentionally downgrading STARTTLS commands has as times been the default configuration for some Cisco routing gear. (Buy me a beer one day and I might tell you about the time I charged one of Australia's big four banks about $70k to debug that in a router on their internal network that nobody there knew existed...)
      • jlgaddis 7y ago
        Which routers did that? I'm well aware that the ASA firewalls did it ("ESMTP inspection") -- I've disabled that dozens of times -- but I've never heard of a router that did it (by default).
    • helper 7y ago
      MTA-STS prevents downgrade attacks.
    • tialaramex 7y ago
      This is often explained in a needlessly confusing way. STARTTLS isn't a problem, the problem is if a user checks a box (or moral equivalent) saying it's optional obviously bad guys will opt for "No". If your client is set to _require_ STARTTLS, then an adversary blocking STARTTLS has the same effect as if they just blocked the IP address of the mail server, you get an error and it doesn't work. There's no reason to use "opportunistic" STARTTLS for your own mail servers (ie IMAP or SMTP to an outbound relay). Nobody should be configuring their own gear, or corporate gear, to just let somebody else decide whether it uses encryption. Opportunistic encryption still has a place in server-to-server SMTP relaying, but if you're choosing options like "if available" in a desktop/phone mail client that's wrong.
      • geocar 7y ago
        It may be better than nothing, but it's far from a sure thing: If you can BGP announce an IP, you can get a certificate from letsencrypt. This is a trivial attack vector not just for state-actors, but also stupid kids: in the early 2000s, I announced Microsoft's AS from my own network (AS21863) to see what would happen and got a significant amount of microsoft.com's traffic. There was no security, and there still isn't: Most multihomed sites that change links frequently inevitably find themselves unfiltered either through accident or misplaced trust. For this reason, TLS without key-pinning (even with IP filtering, as is popular with a lot of banks/enterprise) is far less secure than people realise, and on unattended links (server-to-server relaying) it offers only some casual confidentiality (since detection is unlikely) at best. If you use MTA-STS, you have a good chance of detecting this kind of attack though. I've not seen anyone use a long policy on a distant but popular network to require someone BGP hijack two big networks to beat it, but I suspect such a disruption would be felt across the Internet.
        • tinus_hn 7y ago
          Letsencrypt supposedly has deployed a system that makes the connections from different locations around the world to make this attack more difficult and also you can’t get a letsencrypt certificate for gmail.com or microsoft.com (or Gmail.* or microsoft.* for that matter), there’s a block list for high value targets.
    • throw0101a 7y ago
      > I do however think that it's important to note that opportunistic STARTTLS is vulnerable to downgrade attacks by mitm See SMTP MTA Strict Transport Security (MTA-STS): * https://tools.ietf.org/html/rfc8461 https://tools.ietf.org/html/rfc8461 And STARTTLS Everywhere: * https://starttls-everywhere.org/ https://starttls-everywhere.org/
  • throw0101a 7y ago
    > Any good email client should prohibit you from Most e-mail servers required a login (regardless of fetching or sending), and it would take a real incompetent sysadmin to allow that to happen in the clear.
• dasil003 7y ago
  Are you assuming everyone uses Gmail or do you not know how SMTP works?
  • Godel_unicode 7y ago
    You might be surprised just how many mail providers support STARTTLS for email, at least opportunistically. https://www.fastmail.com/help/technical/ssltlsstarttls.html https://www.fastmail.com/help/technical/ssltlsstarttls.html
    • willvarfar 7y ago
      And opportunistic STARTTLS is vulnerable to downgrade attacks by MITM. the problems with email are that, no matter how sure you are that the connection between you and your mail server, and your local and server storage, are secure, the parties you may be interacting with are not. And then, as is talked about in the article, your recipient forwards the mail as plaintext...
      • delroth 7y ago
        And downgrade attacks are mitigated by MTA-STS: https://www.hardenize.com/blog/mta-sts https://www.hardenize.com/blog/mta-sts Not supported by everyone just yet since this is a new standard, but Gmail at least supports it.
• gsich 7y ago
  Mail doesn't use HTTPS. But even if TLS is enabled, you don't know that all the time.
• thayne 7y ago
  > It's not like I can read your emails unless I break into Google's servers, no? Well, first of all, "breaking in" isn't the only way someone might get access to data on Google's servers. There are such thing's as subpoenas, not to mention that it is possible a Google employee might abuse access to servers. And then I would be _very_ surprised if google doesn't use the content of your emails for advertisement and tracking purposes. Furthermore, unless both parties are using gmail, the email will be stored at least temporarily on other mail servers, which may be less secure (and you might not even know who controls them).
  • wodenokoto 7y ago
    > And then I would be _very_ surprised if google doesn't use the content of your emails for advertisement and tracking purposes. That would go against their own privacy policy. But they are one change away from doing it.
    • garmaine 7y ago
      Really? When gmail came out they were explicitly up front about using the content of the email to deliver targeted ads. Has that changed?
      • justincormack 7y ago
        If you pay Google for email they will not use the content for ads. Free accounts I think they still do.
      • riquito 7y ago
        There are a lot of misinformations around, and the Google haters crowd has plenty of pitchforks. https://safety.google/privacy/ads-and-data/ https://safety.google/privacy/ads-and-data/ > Google does not use keywords or messages in your inbox to show you ads. Nobody reads your email in order to show you ads.
        • comex 7y ago
• meruru 7y ago
  I don't want my emails to be readable by Google, yet they will when people I communicate with are using Gmail.
• cmroanirgo 7y ago
  Any sysadmin can read your email, in general. There's no holistic "this email can't be read by anyone other than the recipient" as a solution, which is what a lot of us are aiming for. Things like protonmail and tutanota get really close, but they're proprietary solutions and don't work for "the many" (such as yourself) who use a hosted solution such as Gmail, who seem to have no interest in providing an open solution.
• loup-vaillant 7y ago
  > It's sent over https, isn't it? That's actually more complicated than that. If you're using a web mail, your connection to the mail provider most likely uses HTTPS. That is, HTTP over TLS. When the mail is sent, it depends whether the recipient uses the same provider or not. If it's the same provider, well, protocols are irrelevant. If not, it will usually be SMTP over TLS (minus any potential problems with STARTTLS). The main problem with that is that the mail is not encrypted on the various servers it goes through. Only the server-to-server connections are encrypted. So your provider can access your email, and so can the recipient's. When that provider's business model is reading your emails so it can send you targeted adds, this is less than great. (Yes, Google reads your emails. They try to reassure you by telling you their employees don't read it, but the fact the process is automated actually makes it worse.)
  • __david__ 7y ago
    Also, it might surprise some people just how many servers an email travels through to get to its destination. I just grabbed a random mail from a mailing list I'm on (generally a worst case scenario) and it had 7 Received headers. Every mail server is supposed to add a Received header when the mail passes through but there's no way to enforce that, so all I can really say is that mail probably passed through at least 7 servers on it's way to my inbox. Each one of those hops may or may not have talked TLS to the next hop. Each one probably wrote the mail out to a disk based mail queue in plaintext. There is nothing preventing any of those 7 servers from keeping around that mail even though they forwarded it on. There is nothing preventing them from indexing the mail for spam or marketing purposes.
• tinus_hn 7y ago
  The old ‘security is hard so let’s not do it’ argument. Emails are not properly encrypted in transit and are available for access at the provider if a court decides to grant a warrant. That might not be enough protection for everyone. It is possible for a determined individual to withstand targeted attacks if he’s careful and willing to make the sacrifices that come with the territory.