4 ms·

I see encrypted connections to/from gmail all the time. Here's an example from a test I just ran: Trusted TLS connection established to gmail-smtp-in.l.google.

I see encrypted connections to/from gmail all the time. Here's an example from a test I just ran: Trusted TLS connection established to gmail-smtp-in.l.google.com[173.194.79.27]:25: TLSv1 with cipher RC4-SHA Anonymous TLS connection established from mail-yh0-f48.google.com[209.85.213.48]: TLSv1 with cipher RC4-SHA

bigiain 13y ago
Hmmm, no Perfect Forward Secrecy on RC4-SHA... Would it be considered paranoid to read anything into the fact that they offer ECDHE-RC4-SHA for https sessions, but only RC4-SHA for SMTP connections?
- joe_bleau 13y ago
  It could be an artifact of my postfix configuration. Looking over a few logfiles, here are the ciphers I've seen recently (all servers, not just gmail): ADH-AES256-SHA (256/256 bits) AES128-SHA (128/128 bits) AES256-SHA (256/256 bits) DHE-RSA-AES256-SHA (256/256 bits) EDH-RSA-DES-CBC3-SHA (168/168 bits) RC4-SHA (128/128 bits)
  - bigiain 13y ago
    Curiously, I'm seeing a bunch of TLSv1:DHE-RSA-AES256-SHA:256 between one of my machines and google... I wonder why/when the connections end up RC4-SHA instead?
    - viveksec 13y ago
      Google serves up static content uses DHE. We've noticed only Google sites using DSA certs with ECDHE. A report on what we found http://trisul.org/blog/dsa-xdrill/post.html http://trisul.org/blog/dsa-xdrill/post.html
- viveksec 13y ago
  > Hmmm, no Perfect Forward Secrecy on RC4-SHA... Actually dont see how you can have PFS on DHE either if one of the endpoints doesnt co-operate. You can simply dump the master keys and provide those to the decrypting app.
  - e12e 13y ago
    Or just dump the plaintext data. If I tell you a secret, and you tell someone else ... there's not a lot I can do a about that. If you don't want a third party to be able to hand over your plaintext (or store it) -- don't give them your plaintext (or a means to access your plaintext). Similarly, if I send you a PGP encrypted email, I can't know if you decrypt that and hand it over to someone else (willingly or unwittingly).
    - bigiain 13y ago
      I can though, still assume that if I send you a GPG encrypted email to your gmail account - I've only got to worry about _you_ leaking the contents, not Google. -----BEGIN PGP MESSAGE----- hQIMA13LrXtLThhwAQ/+LmYMzmaQ3Ui0AF5yRKzCVL/rXzUO3h+cKZVnA2AL/SAR PHcVjgGkm4BT3C8pokeTl+UQPqsBj/i3gteC0zi5QTMyXYxnkCC6915yVGON86BS E5i+pEpXIubnWiKZh81Ik+YARYnTqi+Ea5zW0OAzKmd48FX9m21MK0fKHcdjoYZk 56JaMbTgcSTcW2RIztwQr9EeTnf/XIHsIrhQuOGmZd9kTmbxn9mA+W2AKzgPmv7s Z+RUgEMrbyjNK+s2V/ibPE0CDpBKR6cleWRmAgEknu2Z8QaBIgiv+a64mKMbtL6I H8ZCcM1djgBmXvjfHRwJEvEKEIfJKVQ5Q1SMyskAkWt23CQIbd1toLzx/2e0F0O3 Zjppm+qnBhM6JUOnuc5L42uvZK1+0L3aT99UX5L2xOV8OdqgVto1u+d/Q35LUhNl jjslEKidDxhxFWVHJvVhY/4ogQZIq4WrEpDMoYjRzniECMi779MTl6UnX0vRjVuw 3dbXppozqhB40P7q9Om+ORXGfMrzpIRwABltY6NI5PPjeFgHeNZ/gAFxfWn6INYa mielp57irCYBAVaVIodds2EZNSJ3o8m8A/p4HKbuS8W1qDkU2QY4k+Ns27LY3EQM 0fXx6Ug5INql6vHQpj02W4q4S8A0FipS70WZIH4eWm/aLDWV4PT/0hMoGAhYPgvS lgFoQeoAPeaPJ+Tlb1WX5V7cePBH3EZte+0WcBwlZBBejCBNVAjpyFUG4jMcOv/B IPPa+7IFWjE/1kf7n6e+/OsqDjXWem2j5wJd8R0SJlJk97/VjGDvYAn2mdNCqQ43 /sLRy5oTgEE+kljtFriL5Qfdhkei5UR8RZxV3Yv3J+ARohj7JJovSi0psR9hVI5J BGL2emenig== =Eqf+ -----END PGP MESSAGE-----
      - e12e 13y ago
        Oh, absolutely. I just wanted to point out that if you're communicating with google, you're communicating with google -- so even if they enable perfect forward secrecy over smtp/tls -- that's not a 100% fix. It is still better than them not enabling it -- because if we can assume they do not log the data by default, on their own (aka: we can trust google) -- old data won't be accessible once a (theoretical) new warrant arrives.

bigiain 13y ago

Hmmm, no Perfect Forward Secrecy on RC4-SHA... Would it be considered paranoid to read anything into the fact that they offer ECDHE-RC4-SHA for https sessions, but only RC4-SHA for SMTP connections?

joe_bleau 13y ago
It could be an artifact of my postfix configuration. Looking over a few logfiles, here are the ciphers I've seen recently (all servers, not just gmail): ADH-AES256-SHA (256/256 bits) AES128-SHA (128/128 bits) AES256-SHA (256/256 bits) DHE-RSA-AES256-SHA (256/256 bits) EDH-RSA-DES-CBC3-SHA (168/168 bits) RC4-SHA (128/128 bits)
- bigiain 13y ago
  Curiously, I'm seeing a bunch of TLSv1:DHE-RSA-AES256-SHA:256 between one of my machines and google... I wonder why/when the connections end up RC4-SHA instead?
  - viveksec 13y ago
    Google serves up static content uses DHE. We've noticed only Google sites using DSA certs with ECDHE. A report on what we found http://trisul.org/blog/dsa-xdrill/post.html http://trisul.org/blog/dsa-xdrill/post.html
viveksec 13y ago
> Hmmm, no Perfect Forward Secrecy on RC4-SHA... Actually dont see how you can have PFS on DHE either if one of the endpoints doesnt co-operate. You can simply dump the master keys and provide those to the decrypting app.
- e12e 13y ago
  Or just dump the plaintext data. If I tell you a secret, and you tell someone else ... there's not a lot I can do a about that. If you don't want a third party to be able to hand over your plaintext (or store it) -- don't give them your plaintext (or a means to access your plaintext). Similarly, if I send you a PGP encrypted email, I can't know if you decrypt that and hand it over to someone else (willingly or unwittingly).
  - bigiain 13y ago
    I can though, still assume that if I send you a GPG encrypted email to your gmail account - I've only got to worry about _you_ leaking the contents, not Google. -----BEGIN PGP MESSAGE----- hQIMA13LrXtLThhwAQ/+LmYMzmaQ3Ui0AF5yRKzCVL/rXzUO3h+cKZVnA2AL/SAR PHcVjgGkm4BT3C8pokeTl+UQPqsBj/i3gteC0zi5QTMyXYxnkCC6915yVGON86BS E5i+pEpXIubnWiKZh81Ik+YARYnTqi+Ea5zW0OAzKmd48FX9m21MK0fKHcdjoYZk 56JaMbTgcSTcW2RIztwQr9EeTnf/XIHsIrhQuOGmZd9kTmbxn9mA+W2AKzgPmv7s Z+RUgEMrbyjNK+s2V/ibPE0CDpBKR6cleWRmAgEknu2Z8QaBIgiv+a64mKMbtL6I H8ZCcM1djgBmXvjfHRwJEvEKEIfJKVQ5Q1SMyskAkWt23CQIbd1toLzx/2e0F0O3 Zjppm+qnBhM6JUOnuc5L42uvZK1+0L3aT99UX5L2xOV8OdqgVto1u+d/Q35LUhNl jjslEKidDxhxFWVHJvVhY/4ogQZIq4WrEpDMoYjRzniECMi779MTl6UnX0vRjVuw 3dbXppozqhB40P7q9Om+ORXGfMrzpIRwABltY6NI5PPjeFgHeNZ/gAFxfWn6INYa mielp57irCYBAVaVIodds2EZNSJ3o8m8A/p4HKbuS8W1qDkU2QY4k+Ns27LY3EQM 0fXx6Ug5INql6vHQpj02W4q4S8A0FipS70WZIH4eWm/aLDWV4PT/0hMoGAhYPgvS lgFoQeoAPeaPJ+Tlb1WX5V7cePBH3EZte+0WcBwlZBBejCBNVAjpyFUG4jMcOv/B IPPa+7IFWjE/1kf7n6e+/OsqDjXWem2j5wJd8R0SJlJk97/VjGDvYAn2mdNCqQ43 /sLRy5oTgEE+kljtFriL5Qfdhkei5UR8RZxV3Yv3J+ARohj7JJovSi0psR9hVI5J BGL2emenig== =Eqf+ -----END PGP MESSAGE-----
    - e12e 13y ago
      Oh, absolutely. I just wanted to point out that if you're communicating with google, you're communicating with google -- so even if they enable perfect forward secrecy over smtp/tls -- that's not a 100% fix. It is still better than them not enabling it -- because if we can assume they do not log the data by default, on their own (aka: we can trust google) -- old data won't be accessible once a (theoretical) new warrant arrives.