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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

#61

Post by palant »

orf wrote: post #43
palant wrote: post #37

Earlier quoted context omitted.

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

By "trusted UI" I meant user interface within the browser that clearly doesn't belong to the webpage - such as the browser action's pop-up. As I said, an extension like Keybase could delegate this action to their app. Other extensions don't have this option because they don't have a native component. This is the reason why so many have implemented questionable or outright insecure solutions.

Re: Keybase’s browser extension subverts its encryption

#62

Post by lrvick »

nh2 wrote: post #60
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…

> OpenPGP ... is only adopted by the most hard core of nerds. This seems pretty inaccurate. * Lots of software projects sign their releases with PGP. * Almost all Linux distributions sign their software with PGP. If you use Linux, your security relies critically PGP. * Github has support for PGP, and I see people use it. * My random server hoster happens to sign all their emails with PGP. You could claim that all the…

Even Facebook for all their privacy failings supports it. You can add your public key to your profile and they will encrypt all emails to you.

Re: Keybase’s browser extension subverts its encryption

#63

Post by arglebarnacle »

nh2 wrote: post #60
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…

> OpenPGP ... is only adopted by the most hard core of nerds. This seems pretty inaccurate. * Lots of software projects sign their releases with PGP. * Almost all Linux distributions sign their software with PGP. If you use Linux, your security relies critically PGP. * Github has support for PGP, and I see people use it. * My random server hoster happens to sign all their emails with PGP. You could claim that all the…

The GP was pretty clearly talking about PGP in the context of ordinary encrypted communication between people (like email). Keybase isn't competing with PGP for signing releases. In the field that we are talking about, PGP has absolutely failed to gain widespread traction outside a certain hard core group of nerds.

Re: Keybase’s browser extension subverts its encryption

#64

Post by jedberg »

nh2 wrote: post #60
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…

> OpenPGP ... is only adopted by the most hard core of nerds. This seems pretty inaccurate. * Lots of software projects sign their releases with PGP. * Almost all Linux distributions sign their software with PGP. If you use Linux, your security relies critically PGP. * Github has support for PGP, and I see people use it. * My random server hoster happens to sign all their emails with PGP. You could claim that all the…

Those aren't a representative sample of computer users though. Those are in fact the most hard core of nerds. If you want to take a poll of users, look at even keybase users (already highly biased). How many of them use the PGP key that they had to create when they signed up? I know I don't.

Re: Keybase’s browser extension subverts its encryption

#65

Post by dilatedmind »

phyzome wrote: post #53
dilatedmind wrote: post #23

if you are going to encrypt a message, it must at some point be input without encryption. Just like you wouldn't type a sensitive message with someone looking over your shoulder, you can use common sense and limit use of this extension. Keybase is fantastic. i've been using keybase for 2 years now and have had no issue accessing my files through kbfs. with keybase teams you can store secrets at rest and make them eas…

> if you are going to encrypt a message, it must at some point be input without encryption. How do you feel about someone else composing the message that "you" (your encryption software) are going to encrypt? Because that's what the article is talking about.

I feel like it would be best to avoid using their extension, but I am more concerned with the features and security of their core products.

And I would think it is analogous to running kbfs on a machine with a virus or keylogger.

And one nice thing is your root key is still protected by a paper key which you can physically secure, and use to de auth any compromised device keys.

For the casual user who is just getting into keybase, social integration like this may be worth the risk in order to help onboarding new users. Once they start seeing the real benefits of using keybase, they can delete the extension and still make use of the good stuff.

Finally, keybase is open source right? They are a small team and might not have the resources to improve the extension, but just getting the first iteration out there might be enough to attract contributors who see its value and can improve its security.

Re: Keybase’s browser extension subverts its encryption

#66

Post by FabHK »

Leace wrote: post #14
Legogris wrote: post #2

I have to say I am surprised and disappointed. Keybase has up until now been a shining example of doing crypto right but still accessible and easy to use. This decision falls strictly on the wrong side of the line of acceptable compromises. > there were technical reasons why iframes didn’t work, though I forget the details It could be that there is one or a couple of engineers at Keybase who made this decision and ar…

When they started asking me for my private key and claiming it'll be secure because it's "encrypted" that raised a red flag for me. Then I found out that they're not using popular and audited libraries like OpenPGPjs instead... writing their own!

Filippo Valsorda had a blog post on uploading his private key (back in 2014) in which he actually publicly uploaded his private key - encrypted, that is, as it is uploaded to Keybase [1].

Of course, it goes against orthodoxy to share/upload your private key, but I'm not sure I've ever seen a good rebuttal to Filippo's post.

It seems to me though that you're reducing the entropy of your key from the 2048 bits or whatever to the entropy of your key phrase, which would normally only be some 100 or so bits (if you have a decent one) - but I'm not informed enough to judge the details. However, it seems to me that Filippo is, and he did upload his private key (encrypted) - so how bad is that, really? Anyone got some substantiated insights there?

[1] https://blog.filippo.io/on-keybase-dot-io-and-encrypted-priv...

Re: Keybase’s browser extension subverts its encryption

#67

Post by jwilk »

FabHK wrote: post #66
Leace wrote: post #14

Earlier quoted context omitted.

When they started asking me for my private key and claiming it'll be secure because it's "encrypted" that raised a red flag for me. Then I found out that they're not using popular and audited libraries like OpenPGPjs instead... writing their own!

Filippo Valsorda had a blog post on uploading his private key (back in 2014) in which he actually publicly uploaded his private key - encrypted, that is, as it is uploaded to Keybase [1]. Of course, it goes against orthodoxy to share/upload your private key, but I'm not sure I've ever seen a good rebuttal to Filippo's post. It seems to me though that you're reducing the entropy of your key from the 2048 bits or whate…

Security strength of RSA is much lower than the key size.

2048-bit RSA gives you only ~112 bits of security.

Re: Keybase’s browser extension subverts its encryption

#68

Post by wetKoala »

Keybase is fine for throwaway encryption that only needs short-term wire security to protect data that will be useless next month.

I wouldn't use a keybase key for anything that should be rendered eternally unbreakable, based on side-channel threat analysis alone. Private keys are not something that should be sourced from a website.

Re: Keybase’s browser extension subverts its encryption

#69

Post by daveFNbuck »

jsjohnst wrote: post #26
hjek wrote: post #18

Earlier quoted context omitted.

Which one of those "outside the scope" categories would you say this one falls into then? To me it reads like there's nothing preventing this bug report from deserving a bounty.

None of these bullets are “open and shut cases”, but all are related without needing a major leap, especially the first one. * Content spoofing / text injection * Issues related to software or protocols not under Keybase control * Reports of spam * Vulnerabilities affecting users of outdated or unpatched browsers and platforms Do I agree with their (alleged) actions? NO! But as I know several folks at Keybase persona…

If this vulnerability can fit those 4 categories, what kind of vulnerability would you be confident would qualify for the bounty?

Re: Keybase’s browser extension subverts its encryption

#70

Post by znpy »

als0 wrote: post #51
fastball wrote: post #30

Earlier quoted context omitted.

Facebook later disabled the possibility interacting with its chat via external non-facebook-branded clients (afaik) I don't think that's true, actually. The existence of Caprine[0] seems to suggest otherwise! 0: https://github.com/sindresorhus/caprine

I remember when Pidgin OTR worked fine with the old Facebook Chat, which I believe was based on the XMPP protocol. The move to Facebook Messenger deprecated this API and I don't think it works anymore. In the case of Caprine, it appears not to use any official API and is just scraping the web page for the right elements. This seems quite fragile and also a non-trivial body of code.

this is exactly what i meant. thank you.
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