A vulnerability you know of and choose to ignore IS a backdoor. All the rest is fancy talk.
There is no WhatsApp 'backdoor'
351–360 of 437 posts
Re: There is no WhatsApp 'backdoor'
#352Earlier quoted context omitted.
> The option does not exist, and should not exist. I also think the option should not exist, but according to The Guardian article [0], the option exists: "In WhatsApp’s implementation of the Signal protocol, we have a “Show Security Notifications” setting (option under Settings > Account > Security) that notifies you when a contact’s security code has changed." [0] https://www.theguardian.com/technology/2017/jan/13/…
The option The Guardian is describing there is something like this: When my partner's key changes: [ ] Show me a notification (y/n) What I was talking about was an option like this: When my partner's key changes: [ ] Wait for my manual confirmation before delivering any messages from my partner that are dated after the key change (y/n) To me it's up for debate whether or not the existence of the first option or the f…
Well, there are two options: notification option and confirmation option.
Moxie correctly assumes that confirmation option (require manual confirmation to resend if key changes) should either be enabled for everyone or disabled for everyone, as its state can be determined passively by the server. But it depends on the notification option. His conclusion is that confirmation option should be disabled for everyone because if it is enabled, it is possible to leak notification option state. But it is wrong. More secure solution exists: enable notification option for everyone, and then enable confirmation option for everyone.
I was complaining about why notification should be an option. Even worse, disabled by default.
Wire [0] just shows "resend" button near message when it is not delivered and always shows notifications about key changes if you have verified devices. You can still ignore verification option if you want and get no notifications.
Signal blocks with a message when key changes.
Both solutions are secure, Wire's is more convenient, Signal is less error-prone. WhatsApp solution is simply insecure.
Re: There is no WhatsApp 'backdoor'
#353Earlier quoted context omitted.
I was actually perplexed, after reading about signal, that I couldn't just download an APK. Are play services required for signal? If so, can I even install signal on a cyanogenmod phone? Can you do so by rebuilding it yourself? Does the build match the shipped binary on the play store? To me, Signal does look exactly in the same boat as whatsapp. The fact that WhisperSystems didn't cooperate harder to ship Signal in…
Wire uses the signal protocol. [1] I am not sure if they require google play services but I thought saw something a while back on their github regarding a fallback if google services was not installed and battery consumption. [1] https://wire.com/download/
Wire uses Firebase Cloud Messaging (former Google Cloud Messaging) by default as it is the Google requirement. If you, as a developer, roll out your own solution, you simply get banned on Google Play. Claimed reason is that FCM/GCM delivers all your messages in batch, so it saves your phone power [0]. It is doubtful because your phone may enter Discontinuous Reception (DRX) state, so your cellular operator will deliver messages in batch anyway, but whatever. I think it is Google pushing developers to use their push servers while avoiding antitrust laws.
GitHub message about fallback to WebSocket you are referring to is here: [1]. So you can remove all Google services from your phone and install APK, it will still work, but now Wire server pings your phone whenever it wants. TLDR on the thread is that APK is not uploaded to F-Droid due to dependency (not really) on Google services.
[0] https://developer.android.com/training/monitoring-device-sta...
[1] https://github.com/wireapp/wire-android/issues/5#issuecommen...
Re: There is no WhatsApp 'backdoor'
#354Earlier quoted context omitted.
Difference is that the WhatsApp client re-encrypts the message with the new key from the server and re-sends it without user intervention ("non-blocking"), so even if you cared, you can't prevent it. With the alternative, people that don't care could tick "verified" with or without verifying, but you could also click "cancel" (with or without verifying).
What difference does it make? ALICE When would you like to meet? BOB Tomorrow, 19:00, by the north tennis courts. ALICE Sounds good. !!! BOB's key has changed !!! BOB Actually, could we meet at my place? I'm going to be super busy tomorrow. If Alice and Bob are doing something that needs to remain secure, Alice would be a fool to trust Bob's messages after the key change without manually verifying the new key with Bo…
BOB: Ok, we're all good, we have verified our keys in person, send me the launch keys to the nuclear missile. Good night. [tick mark, tick mark]
ALICE: Here they are: 12345678. [tick mark]
[Eve on the compromised server to Alice]: Hey ho, new key, please send again.
ALICE [with new MITM key, and no way to block this]: Here they are: 12345678.
!!! By the way, Bob's key has changed. !!!
BOTH: Ooops.
Re: There is no WhatsApp 'backdoor'
#355Earlier quoted context omitted.
> But "verified" software often means formal mathematical verification, and that is orthogonal to if the source is open. I think there may be cross-talk here related to who's doing the verifying too. I think the parent is assuming "verification" would imply that a 3rd party could verify the software in question. AFAIUI it's currently nowhere near practical for a 3rd party to verify closed-source software of any non-t…
Downthread tptacek talks about how his company does verification of binary images. I assume there are limits to what is possible, but that's really the same as any verification approach. I do agree that 'who is verifying' is a valid way of looking at it too. Regardless, it's pretty clear that tptacek means formal verification. Edit: see http://arieg.bitbucket.org/pdf/seahorn.pdf
My company doesn't do this. But many companies specialize in it.
Re: There is no WhatsApp 'backdoor'
#356Earlier quoted context omitted.
> Bob's answers contain the "delivery receipt". I've not seen any specific claims about the mechanism for the delivery receipt - can you link me to this? It's not even clear to me that the delivery receipt is signed.
It's also not clear that the server must forward all the delivery receipts before it forwards the later replies. Could it just eat them all? EDIT: after a quick look at the spec¹, it seems that it supports out-of-order messages, meaning the server could selectively eat receipts. [1] https://whispersystems.org/docs/specifications/doubleratchet...
So, given that, it would seem that a compromised server could pull a whole conversation (if people overlook the single tick mark), as claimed in the article?
Re: There is no WhatsApp 'backdoor'
#357Earlier quoted context omitted.
this requires humans to be able to generate and remember passwords with decent entropy
That was just an example. You could also pair the key to a person by some other method, such as storing a copy of it on a storage medium other than their phone.
Requiring a external storage medium would kill the service. I think you have to separate a service made for the masses and a service with focus on security/encryption. For WhatsApp there will be some instances where you have to choose between security and convince, and they have choose the former, which is only naturally.
Re: There is no WhatsApp 'backdoor'
#358Earlier quoted context omitted.
I was actually perplexed, after reading about signal, that I couldn't just download an APK. Are play services required for signal? If so, can I even install signal on a cyanogenmod phone? Can you do so by rebuilding it yourself? Does the build match the shipped binary on the play store? To me, Signal does look exactly in the same boat as whatsapp. The fact that WhisperSystems didn't cooperate harder to ship Signal in…
Used to be, called LibreSignal. They ran into legal issues. https://github.com/LibreSignal/LibreSignal There is a bounty for modifying the signal app source to drop play services. https://www.bountysource.com/issues/35722527-create-proper-p...
They can't use the name LibreSignal because it has the word Signal in it?
Wow, even Microsoft didn't behave that juvenile about LibreOffice.
Re: There is no WhatsApp 'backdoor'
#359Earlier quoted context omitted.
I was actually perplexed, after reading about signal, that I couldn't just download an APK. Are play services required for signal? If so, can I even install signal on a cyanogenmod phone? Can you do so by rebuilding it yourself? Does the build match the shipped binary on the play store? To me, Signal does look exactly in the same boat as whatsapp. The fact that WhisperSystems didn't cooperate harder to ship Signal in…
Wire uses the signal protocol. [1] I am not sure if they require google play services but I thought saw something a while back on their github regarding a fallback if google services was not installed and battery consumption. [1] https://wire.com/download/
They don't use the signal protocol, they don't even use X3DH or Double Ratchet. That citation of yours is just a download link, not an actual reference to your point.
The project is also kind of a mess. Check out their privacy policy, Wire maintains a server side copy of your entire contact list, all the groups that you're in, the plaintext metadata for your groups (membership, plaintext group title, plaintext group avatar).
Check out some of the code. They have broken voice encryption, and leak enough data to reconstruct the audio of your calls. They leak tons of plaintext directly back to themselves, like searches, and rolled their own messaging crypto.
They have been caught lying about what kind of encryption they provide[1], they lied about being open source for years, they lied about being based in switzerland. From what I can tell, the only people promoting Wire are usually on Wire's marketing team.
1: http://www.pcworld.com/article/2855745/new-communications-ap...
Re: There is no WhatsApp 'backdoor'
#360Earlier quoted context omitted.
That was just an example. You could also pair the key to a person by some other method, such as storing a copy of it on a storage medium other than their phone.
Requiring a external storage medium would kill the service. I think you have to separate a service made for the masses and a service with focus on security/encryption. For WhatsApp there will be some instances where you have to choose between security and convince, and they have choose the former, which is only naturally.
I didn't say it has to solely reside on the storage medium. The phone can keep a copy and a user can make a backup.