9 ms·

> We didn't review the entire source code Then it's not fully investigated. That should put any assessments to rest.

3rodents 8mo ago
By that standard, it can never be verified because what is running and what is reviewed could be different. Reviewing relevant elements is as meaningful as reviewing all the source code.
- giancarlostoro 8mo ago
  Or they could even take out the backdoor code and then put it back in after review.
  - taneq 8mo ago
    Ah yes, the Volkswagen solution.
    - KellyCriterion 8mo ago
      ++1 "target market product alignment" :-D
  - hedora 8mo ago
    This is why signal supports reproducible builds.
    - pdpi 8mo ago
      In this day and age, in a world with Docker and dev containers and such, it's kind of shocking that reproducible builds aren't table stakes.
    - LtWorf 8mo ago
      Does it still require the gigantic binary blob?
- dangus 8mo ago
  Let’s be real: the standard is “Do we trust Meta?” I don’t, and don’t see how it could possibly be construed to be logical to trust them. I definitely trust a non-profit open source alternative a whole lot more. Perception can be different than reality but that’s what we’ve got to work with.
Barrin92 8mo ago
as long as client side encryption has been audited, which to my understanding is the case, it doesn't matter. That is literally the point of encryption, communication across adversarial channels. Unless you think Facebook has broken the laws of mathematics it's impossible for them to decrypt the content of messages without the users private keys.
- maqp 8mo ago
  Well the thing is, the key exfiltration code would probably reside outside the TCB. Not particularly hard to have some function grab the signing keys, and send them to the server. Then you can impersonate as the user in MITM. That exfiltration is one-time and it's quite hard to recover from. I'd much rather not have blind faith on WhatsApp doing the right thing, and instead just use Signal so I can verify myself it's key management is doing only what it should. Speculating over the correctness of E2EE implementation isn't productive, considering the metadata leak we know Meta takes full advantage of, is enough reason to stick proper platforms like Signal.
  - subw00f 8mo ago
    Not that I trust Facebook or anything but wouldn’t a motivated investigator be able to find this key exfiltration “function” or code by now? Unless there is some remote code execution flow going on.
    - impure-aqua 8mo ago
      WhatsApp performs dynamic code loading from memory, GrapheneOS detects it when you open the app, and blocking this causes the app to crash during startup. So we know that static analysis of the APK is not giving us the whole picture of what actually executes. This DCL could be fetching some forward_to_NSA() function from a server and registering it to be called on every outgoing message. It would be trivial to hide in tcpdumps, best approach would be tracing with Frida and looking at syscalls to attempt to isolate what is actually being loaded, but it is also trivial for apps to detect they are being debugged and conditionally avoid loading the incriminating code in this instance. This code would only run in environments where the interested parties are sure there is no chance of detection, which is enough of the endpoints that even if you personally can set off the anti-tracing conditions without falling foul of whatever attestation Meta likely have going on, everyone you text will be participating unknowingly in the dragnet anyway.
ghurtado 8mo ago
I have to assume you have never worked on security cataloging of third party dependencies on a large code base. Because if you had, you would realize how ridiculous it is to state that app security can't be assessed until you have read 100% of the code That's like saying "well, we don't know how many other houses in the city might be on fire, so we should let this one burn until we know for sure"
- jokersarewild 8mo ago
  It sounds like your salary has depended on believing things like a partial audit is worthwhile in the case that a client is the actual adversary.
  - charcircuit 8mo ago
    Except Meta is not an adversary. They are aligned with people who want private messaging.
    - mikkupikku 8mo ago
      Brutal sarcasm.
- fasbiner 8mo ago
  What you are saying is empirically false. Change in a single line of executed code (sometimes even a single character!) can be the difference between a secure and non-secure system. This must mean that you have been paid not to understand these things. Or perhaps you would be punished at work if you internalized reality and spoke up. In either case, I don't think your personal emotional landscape should take precedence over things that have been proven and are trivial to demonstrate.
  - JasonADrury 8mo ago
    > Change in a single line of executed code (sometimes even a single character!) can be the difference between a secure and non-secure system. This is kind of pointless, nobody is going to audit every single instruction in the Linux kernel or any complex software product.

By that standard, it can never be verified because what is running and what is reviewed could be different. Reviewing relevant elements is as meaningful as reviewing all the source code.

giancarlostoro 8mo ago
Or they could even take out the backdoor code and then put it back in after review.
- taneq 8mo ago
  Ah yes, the Volkswagen solution.
  - KellyCriterion 8mo ago
    ++1 "target market product alignment" :-D
- hedora 8mo ago
  This is why signal supports reproducible builds.
  - pdpi 8mo ago
    In this day and age, in a world with Docker and dev containers and such, it's kind of shocking that reproducible builds aren't table stakes.
  - LtWorf 8mo ago
    Does it still require the gigantic binary blob?
dangus 8mo ago
Let’s be real: the standard is “Do we trust Meta?” I don’t, and don’t see how it could possibly be construed to be logical to trust them. I definitely trust a non-profit open source alternative a whole lot more. Perception can be different than reality but that’s what we’ve got to work with.

Barrin92 8mo ago

as long as client side encryption has been audited, which to my understanding is the case, it doesn't matter. That is literally the point of encryption, communication across adversarial channels. Unless you think Facebook has broken the laws of mathematics it's impossible for them to decrypt the content of messages without the users private keys.

maqp 8mo ago
Well the thing is, the key exfiltration code would probably reside outside the TCB. Not particularly hard to have some function grab the signing keys, and send them to the server. Then you can impersonate as the user in MITM. That exfiltration is one-time and it's quite hard to recover from. I'd much rather not have blind faith on WhatsApp doing the right thing, and instead just use Signal so I can verify myself it's key management is doing only what it should. Speculating over the correctness of E2EE implementation isn't productive, considering the metadata leak we know Meta takes full advantage of, is enough reason to stick proper platforms like Signal.
- subw00f 8mo ago
  Not that I trust Facebook or anything but wouldn’t a motivated investigator be able to find this key exfiltration “function” or code by now? Unless there is some remote code execution flow going on.
  - impure-aqua 8mo ago
    WhatsApp performs dynamic code loading from memory, GrapheneOS detects it when you open the app, and blocking this causes the app to crash during startup. So we know that static analysis of the APK is not giving us the whole picture of what actually executes. This DCL could be fetching some forward_to_NSA() function from a server and registering it to be called on every outgoing message. It would be trivial to hide in tcpdumps, best approach would be tracing with Frida and looking at syscalls to attempt to isolate what is actually being loaded, but it is also trivial for apps to detect they are being debugged and conditionally avoid loading the incriminating code in this instance. This code would only run in environments where the interested parties are sure there is no chance of detection, which is enough of the endpoints that even if you personally can set off the anti-tracing conditions without falling foul of whatever attestation Meta likely have going on, everyone you text will be participating unknowingly in the dragnet anyway.

ghurtado 8mo ago

I have to assume you have never worked on security cataloging of third party dependencies on a large code base. Because if you had, you would realize how ridiculous it is to state that app security can't be assessed until you have read 100% of the code That's like saying "well, we don't know how many other houses in the city might be on fire, so we should let this one burn until we know for sure"

jokersarewild 8mo ago
It sounds like your salary has depended on believing things like a partial audit is worthwhile in the case that a client is the actual adversary.
- charcircuit 8mo ago
  Except Meta is not an adversary. They are aligned with people who want private messaging.
  - mikkupikku 8mo ago
    Brutal sarcasm.
fasbiner 8mo ago
What you are saying is empirically false. Change in a single line of executed code (sometimes even a single character!) can be the difference between a secure and non-secure system. This must mean that you have been paid not to understand these things. Or perhaps you would be punished at work if you internalized reality and spoke up. In either case, I don't think your personal emotional landscape should take precedence over things that have been proven and are trivial to demonstrate.
- JasonADrury 8mo ago
  > Change in a single line of executed code (sometimes even a single character!) can be the difference between a secure and non-secure system. This is kind of pointless, nobody is going to audit every single instruction in the Linux kernel or any complex software product.