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Keybase’s browser extension subverts its encryption

palant.de

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Re: Keybase’s browser extension subverts its encryption

#41

Post by nickik »

lrvick wrote: post #17
Leace wrote: post #16

Earlier quoted context omitted.

This description perfectly captures my impression on Keybase too (especially the part on unwillingness to decentralize their social-media based identities). For the record it soon may be possible to use native GnuPG through the browser extension: > Installer: New optional module "Browser Integration" to register GnuPG as backend for Mailvelope 3.0. Source: https://www.gpg4win.org/change-history.html But given Keybase…

Any trust went out the window when I realized I could pull out my smartcard and continue signing things. My head exploded.

You just don't seem to understand how the service you are using works and guess what. Its different then pure PG. It was not designed to work with your smart-card as it is not primarily about that.

Guess what, other people like me just realized that Keybase was not designed to be used like that and didn't use the smart-card together with Keybase.

I guess you can fault them for not saying that explicitly but since the made no mention of smart-cards and didn't evolve the security model in that direction it was pretty clear that that was not what they were about and therefore I did not expect it to be optimal to be used like that.

Re: Keybase’s browser extension subverts its encryption

#42

Post by walterbell »

ReverseCold wrote: post #36
giancarlostoro wrote: post #25

Earlier quoted context omitted.

Have you tried / compared Wire[0] by chance? I love Wire cause it's simple, my only recommendation is to register from a browser on your desktop, it asks for your number on the phone app, but you don't need to register like that. I also like that you can delete your account and nuke everything. The back-end is open source as well. Though KeyBase gets the UI / UX factor perfect, I wish some hardcore crypto devs would…

Wire's apps feel slow and bloated on both desktop and mobile. Compared to Telegram, Wire is almost unusable.

As a user, Wire has been fast and reliable and usable (even by non-techies) on iOS for several years, across a wide range of network conditions and hostile networks.

They are contributing to an IETF protocol (“MLS”) for E2E messaging, which is a long-term path to messenger interoperability.

Re: Keybase’s browser extension subverts its encryption

#43

Post by orf »

palant wrote: post #37
adambrenecki wrote: post #8

> Avoiding it is fairly easy, by isolating all of the extension’s user interface in an element. Right, but if the social network website can modify the HTML that the Keybase extension is injecting, then surely it can also modify the iframe's URL to an attacker-controlled one? Or, for that matter, replace the event handler on the "Keybase Chat" button itself before it even gets clicked? I'm not an extension developer,…

Yes, I didn't bother expanding this further. Spoofing Keybase UI would still be possible, but users would notice that their message doesn't get sent. Still, the only complete solution would be to delegate even the initial message to the app rather than asking uses to enter it on the webpage. Unfortunately, browsers don't let extensions open trusted UI at will...

Sure they do, you just get a prompt saying 'you sure you want to open keybase?', with the option to skip this prompt in the future

Re: Keybase’s browser extension subverts its encryption

#45

Post by lettergram »

So I wrote essentially the same chrome extension (albeit a different interface, which definitely allows for this vulnerability):

http://lettergram.github.io/AnyCrypt/

https://github.com/lettergram/AnyCrypt

https://chrome.google.com/webstore/detail/anycrypt/hddfngccl....

It worked fairly well (haven't tested it in a bit), but I had to reverse engineer pretty much all the Keybase APIs at the time.

The thing is, the author is totally correct. I wrote mine as a proof of concept, and quite frankly was surprised that the Keybase chrome extension (even a year ago when I checked) had the same issue(s) my implementation did...

That being said, this isn't an "end-of-the-world" kind of thing, I think there are several easy solutions to this problem as the author pointed out. Personally though, only 3 people use my extension with me. I couldn't get anyone to use the Keybase extension.. so I really think they should just update that phrasing on their extension page (perhaps add a warning) and let it be.

Re: Keybase’s browser extension subverts its encryption

#46

Post by Angostura »

nickik wrote: post #20
lrvick wrote: post #13

Keybase also silently subverts smartcards for in-memory keys per my findings here: https://github.com/keybase/keybase-issues/issues/1946 In general I find Keybase to be a step forward in user experience and two steps backwards in terms of actual security. They just don't seem to care about the latter at all and have not demonstrated any cooperation with standards bodies like the OpenPGP working group where members ha…

They don't throw everything on the blockchain for no reason. They specifically back up the root of the merkel tree into the blockchain. Honestly, the OpenPGP world has so competently failed at usability and is only adopted by the most hard core of nerds. Even I have stopped using it for the most part. And that it is two steps back in security overall is just not true. Maybe in some individual features that you care a…

> crypto that nobody is using is not protecting anything.

There's only one thing that's worse. Crypto that people think is protecting them, but which isn't.

Re: Keybase’s browser extension subverts its encryption

#48

Post by patcheudor »

It cannot be said often enough: when you reference someone else's JavaScript in your solution in a way in which it has access to either the DOM or user interface components, it's no longer your solution. You therefore cannot, with any level of integrity claim that your solution is secure as you simply don't know what's happening in that bit of JS which is loaded by the solution into the user-space.

Re: Keybase’s browser extension subverts its encryption

#49

Post by nickik »

Angostura wrote: post #46
nickik wrote: post #20

Earlier quoted context omitted.

They don't throw everything on the blockchain for no reason. They specifically back up the root of the merkel tree into the blockchain. Honestly, the OpenPGP world has so competently failed at usability and is only adopted by the most hard core of nerds. Even I have stopped using it for the most part. And that it is two steps back in security overall is just not true. Maybe in some individual features that you care a…

> crypto that nobody is using is not protecting anything. There's only one thing that's worse. Crypto that people think is protecting them, but which isn't.

Yeah but for the most part Keybase is not that. The person above point out one special case and not for the whole system.

For the most part Keybase crypto is modern, effective and easy to use.

Re: Keybase’s browser extension subverts its encryption

#50

Post by throwanem »

This isn't a hard bug to avoid, but it would take completely reimplementing the extension so that all of its UI beyond the "keybase chat" button lives in the extension rather than being injected into the page, and having the chat button do nothing but call the extension with the username of the intended recipient.

I understand why Keybase principals don't want to do that, because the extension is an addon that probably doesn't do anything in particular for them as far as adoption goes. I'm not sure I understand why they continue to ship the existing extension, knowing that it's insecure.

And I don't see any excuse at all for editing the bug report on Github out of existence - that strikes me as sufficiently sketchy that I may no longer use Keybase at all, and certainly will no longer rely on it to be especially secure.

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