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WhatsApp end-to-end encrypted backups security assessment

research.nccgroup.com

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Re: WhatsApp end-to-end encrypted backups security assessment

#51

Post by triumphantomato »

x86_64Ubuntu wrote: post #49
triumphantomato wrote: post #43

Earlier quoted context omitted.

These look like messages being re-sent from the service to the client. This is not surprising - when you ask someone else to route messages for you, even encrypted messages, you are giving them the (encrpyted) payload and asking them to route it for you. If you have a large network with billions of users, it's reasonable that some of the users' phones may be offline some of the time. Should the service just drop mess…

I'm not sure if that explains why deleted messages from months ago are being resurrected. That would imply that there is a persistence framework that has multi-month readback capability.

The oldest message from the twitter screenshot looks ~8 days old.

In the second tweet the user says "3 chats before the outage and now 15+ or more chats which I deleted before the week or two."

Two weeks (and in screenshots, only 8 days shown) does not seem surprising. Especially given the increasing rate of internet shutdowns across the globe [1].

E2EE is too important to play fast and loose with.

[1] "In 2020, Access Now and the #KeepItOn coalition documented at least 155 internet shutdowns in 29 countries." (https://www.accessnow.org/keepiton/)

Re: WhatsApp end-to-end encrypted backups security assessment

#52

Post by polyomino »

GekkePrutser wrote: post #46
lmm wrote: post #39

Earlier quoted context omitted.

> Why on earth do people trust a closed source messenger owned by Facebook, which backs up to Google? Those are some of the few companies that are large enough to oppose governments. > Signal and Matrix are open source The main advantage of which is to enable audits like this, which WhatsApp is doing. Of course you can't actually build WhatsApp from the audited source or pin it to the audited version... but you can't…

> Those are some of the few companies that are large enough to oppose government They're more likely to cooperate with governments because they have so much to lose. All the big guys are caving in to China for example because they don't want to lose that sweet 1+ billion consumer market. Yes even Google. Check maps.google.cn and see the border around the South China Sea. And also their interests are much more aligned…

Facebook is in china? News to me.

Re: WhatsApp end-to-end encrypted backups security assessment

#53

Post by dancemethis »

romanhn wrote: post #42
encryptluks2 wrote: post #34

I can tell you first hand, anytime a company pays a third party to do a security assessment, the result is purely what the company wants you to see. Independent does not mean that it wasn't influenced, just that it wasn't done by the company itself.

NCC Group is a legit outfit, a public company in fact, so this comment is not warranted.

There is no proof what they tested was actually what's in people's phones. It's most likely a separate "cleaned-up" build/codebase for looks. And chances are against users.

Re: WhatsApp end-to-end encrypted backups security assessment

#54

Post by thevardanian »

jensensbutton wrote: post #26
jakecopp wrote: post #15

Why on earth do people trust a closed source messenger owned by Facebook, which backs up to Google? Signal and Matrix are open source and full-featured.

Because the number of people who can actually validate the security of the open source options is vanishingly small and assessments like this provide sufficient evidence that WhatsApp's claims are not bunk.

You just need one. Vanishingly small or not.

Re: WhatsApp end-to-end encrypted backups security assessment

#55

Post by rOOb85 »

AnonC wrote: post #48
grayhatter wrote: post #35

Earlier quoted context omitted.

Signal doesn't get credit for being open source.

Are you saying it’s not getting enough credit or that it shouldn’t? The Signal code was closed source for longer than a year (from April 2020) when no commits were done in the public repo because . Some months ago the public repo got a barrage of commits after that long gap. It wasn’t that the Signal platform and client had no updates during this time. There were many, but the code wasn’t released. Signal may be open…

> The Signal code was closed source for longer than a year (from April 2020)

This absolutely untrue. Signals source has NEVER been closed source. The Signal server source code(which isn't special and doesn't change that often) just had no public commits. The Signal client source code(what matters and makes Signal secure) was frequently updated.

> Signal may be open source at times,

Again, Signal has always been open source.

Re: WhatsApp end-to-end encrypted backups security assessment

#56

Post by eitland »

jensensbutton wrote: post #26
jakecopp wrote: post #15

Why on earth do people trust a closed source messenger owned by Facebook, which backs up to Google? Signal and Matrix are open source and full-featured.

Because the number of people who can actually validate the security of the open source options is vanishingly small and assessments like this provide sufficient evidence that WhatsApp's claims are not bunk.

> Because the number of people who can actually validate the security of the open source options is vanishingly small

The people who can judge if Facebook are to be trusted should be in the millions by now though...

Re: WhatsApp end-to-end encrypted backups security assessment

#57

Post by tptacek »

romanhn wrote: post #42
encryptluks2 wrote: post #34

I can tell you first hand, anytime a company pays a third party to do a security assessment, the result is purely what the company wants you to see. Independent does not mean that it wasn't influenced, just that it wasn't done by the company itself.

NCC Group is a legit outfit, a public company in fact, so this comment is not warranted.

And this isn't just NCC Group; it's NCC Crypto, a particularly hardcore practice inside of NCC. Marie-Sarah Lacharité's name is on this, and she's not messing around.

Re: WhatsApp end-to-end encrypted backups security assessment

#58

Post by cassonmars »

motohagiography wrote: post #36
bsaul wrote: post #10

Earlier quoted context omitted.

what's the threat this hsm is adding protection against ? i don't mean to be ironic, i genuinely couldn't understand after reading the paper.

I was surprised to read that OPAQUE. uses/generates deterministic asymmetric keypairs based on a secret seed. I'd posit the HSM stores this seed so that it can use various derivations to verify whether a given key asserted by a client was generated by that seed. ( https://www.ietf.org/id/draft-irtf-cfrg-opaque-07.html ) I have only used key derivation in symmetric protocols, so tbh I don't know how you do determinist…

It can effectively be the same. Consider ECDH as key agreement, passed into a KDF such as a hashing algorithm, potentially with additional input, then using that value as the private key — the security assumptions then become the Square Computational Diffie-Hellman and whatever assumption(s) are in the hashing algorithm, the former is proven to be equivalent difficulty to the general CDH assumption.

Re: WhatsApp end-to-end encrypted backups security assessment

#59

Post by dkdk8283 »

rkoten wrote: post #41
WillSmithPro wrote: post #6

I came across this twitter thread during the last Facebook outage. Apparently something very wrong is happening there with their backups. I would definitely check similar cases. Confirmed by multiple people :/ I quote the author: This is really weird. In #WhatsApp, I started to see messages that I know 100% that I deleted 2 days ago?! WTF is happening there? I think this is a really big violation of privacy! I see th…

Durov posting about this in his Telegram channel in 3... 2... 1...

what channel is that?

Re: WhatsApp end-to-end encrypted backups security assessment

#60

Post by sullivanmatt »

encryptluks2 wrote: post #34

I can tell you first hand, anytime a company pays a third party to do a security assessment, the result is purely what the company wants you to see. Independent does not mean that it wasn't influenced, just that it wasn't done by the company itself.

I've coordinated an NCC crypto audit, and I can assure you that is not the case.
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