[liberationtech] Mailvelope: OpenPGP Encryption for Webmail

[Uncle Zzzen]

The reason why FireGPG no longer ships with tails is that the DOM of a web
app is not a safe place for plaintext
https://tails.boum.org/doc/encryption_and_privacy/FireGPG_susceptible_to_devastating_attacks/
Any architecture where plaintext is stored inside a web app's DOM is
dangerous. Especially a webmail app that can be expected to save drafts,
but not only. Web apps can be MITMed, XSSed, etc. If it came via the web,
it's a suspect.

I'd expect a crypto add-on to only accept plaintext (and other sensitive)
information via separate GUI that can only be launched manually (not via
javascript in an app's DOM) and has a hard-to-imitate look-and-feel (to
discourage phishing). The only communication between this add-on and the
rest of the browser should be via the clipboard. Users who can't handle
copy/paste shouldn't be trusted with a key pair :)

>From what I see at the http://www.mailvelope.com/ slide-show, it seems to
provide even more shooting-yourself-in-the-leg firepower than FireGPG.


On Wed, Dec 12, 2012 at 3:21 AM, Nadim Kobeissi <nadim at nadim.cc> wrote:

> Cryptocat is a local browser plugin served over SSL, installed locally,
> loads/executes no external code, and communicates only via SSL. It does not
> rely on server integrity with regards to these parameters.
>
> Regarding Mailvelope b does its operation depend on the Gmail DOM? What
> happens if the Gmail DOM is modified, can that be used to damage the
> integrity of Mailvelope operations? There's a reason Cryptocat operates in
> its own browser tab separate from other sites.
>
> NK
>
> On 2012-12-11, at 6:54 PM, Andy Isaacson <adi at hexapodia.org> wrote:
>
> > On Mon, Dec 10, 2012 at 10:07:23PM +0000, StealthMonger wrote:
> >> "Fabio Pietrosanti (naif)" <lists at infosecurity.ch> writes:
> >>> for whose who has still not see that project, i wanted to send a notice
> >>> about MailVelope, OpenPGP encryption for webmail:
> http://www.mailvelope.com
> >>
> >>> It's a client-side, plug-in based (similar to CryptoCat), OpenPGP email
> >>> encryption plugin available for Chrome and Firefox.
> >>
> >> To compare it with CryptoCat is unfair to MailVelope.  As I understand
> >> things, CryptoCat has an ongoing reliance on server integrity.  On the
> >> other hand, MailVelope is self-contained once securely installed,
> >
> > I'm not sure why you claim that.  It was true for Cryptocat v1 which was
> > a browser app and could be compromised at any time with new JS from a
> > compromised server.  Cryptocat v2 is a downloadable + installable plugin
> > which at least doesn't immediately execute code served to it.
> >
> > In both the JS and plugin versions, Cryptocat (with uncompromised code)
> > does not depend on server integrity for message confidentiality.
> >
> > Now, both CryptoCat and MailVelope probably have an upgrade
> > vulnerability where a compromised server can tell the app "there's a new
> > version available, plese ask the user to install it".  And since the
> > compromised server could refuse to provide service to the secure version
> > of the app, there's a powerful functional reason for the user to accept
> > the upgrade.
> >
> > Ah, perhaps you're referring to the fact that MailVelope layers on top
> > of another server (Gmail) for its transport layer, rather than depending
> > on a "MailVelope server" which could selectively deny service to the
> > uncompromised version of the product.  In that respect, MailVelope might
> > be more secure-by-design than Cryptocat.
> >
> > -andy
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