6 ms·

The most backdoor-looking feature for me in supposedly encrypted systems are cloud backups. They are “optional” yet most users will agree (especially when given

The most backdoor-looking feature for me in supposedly encrypted systems are cloud backups. They are “optional” yet most users will agree (especially when given software constantly nags about it until you give up) and their backups will leak both sides of conversations, despite all end-to-end encryption attempts.

londons_explore 6y ago
WhatsApps cloud backup on Android sits on Google drive by default. It is encrypted with a per user key known to WhatsApp. That means for a third party to access the chats, they need Google to hand over the data, and Facebook to hand over the key. The logical next step to add would be for Google to additionally encrypt the data with the users logon password or something derived from it. Google won't do this anytime soon for business reasons.
- garmaine 6y ago
  > That means for a third party to access the chats, they need Google to hand over the data, and Facebook to hand over the key. National intelligence agencies (plural) would already have both.
  - londons_explore 6y ago
    True, but it still makes the attack surface much smaller - employees of neither company could steal your data. Your data is now protected by the intersection of the companies privacy policies rather than the union of them.
    - beagle3 6y ago
      It used to be that way. But then, one day, Google announced that WhatsApp backups (a) no longer count towards your quota, and (b) are no longer encrypted. There are two beneficiaries of this change: 1) Intelligence and law enforcement agencies, which now have direct access to WhatsApp history for everyone who uses cloud backup (99.9% of users, if not 100%), without the need to 0day any specific phones, risk detection, or even have those phones on except occasionally. 2) Google, who can now mine your private conversations, metadata, etc. (At a tiny storage cost for Google, for which they are likely compensated by the NSA)
- paranoidrobot 6y ago
  > encrypt the data with the users logon password or something derived from it This leads to inability to restore a backup if you forget your password and need to reset it. That's going to lead to screams/tears from a lot of folks who don't realise those implications.
- sdflhasjd 6y ago
  WhatsApp backups are a bit of an anti-feature, as I found out while trying to ditch the app after the recent policy update. 1) The backup can only be made to Google drive, you cannot create a manual backup to a location of your chosing 2) The backup is created in a secret folder that cannot be accessed by the user 3) The backup is deleted if you delete your account. (not much of a backup, eh?) 4) You can only create per-channel exports, but this won't export the entire chat, it will export up to ~12MB of recent media, and ignore the rest, silently. WhatsApp would only share the last 40 messages of a 4-year-old chat because the last few messages contained a few images.
  - londons_explore 6y ago
    I believe there is still an (undocumented, unofficial) way to backup to the SD card. The backup is still encrypted tho, and can only be restored to the same whatsapp account as created it.
  - ycombinete 6y ago
    Interesting. I just created a 900MB backup of a chat history, on my iOS WhatsApp, that appears to have all messages and all data.
    - tinus_hn 6y ago
      Being an iOS device it probably doesn’t ‘backup’ to Google Drive so this story may not apply
      - ycombinete 6y ago
        yeah, on ios whatsapp backs up the data to icloud
  - jsmith99 6y ago
    I can't find any source for this 12MB limit? Backups I've restored (Android) seen to contain all media although I haven't checked in detail.
- keyme 6y ago
  I've posted this here before. > It is encrypted with a per user key known to WhatsApp. This is no longer true! For a few years now. The backup is stored on Google Drive in plain text. https://faq.whatsapp.com/android/chats/about-google-drive-backups/?lang=fb https://faq.whatsapp.com/android/chats/about-google-drive-ba...
  - FiloSottile 6y ago
    That page doesn't say that, and "tied to the phone number" sounds like they will only give you the key if you can authenticate via SMS. Do you have a better cite or did you check directly recently?
    - londons_explore 6y ago
      > authenticate via SMS It's now "authenticate via SMS and pin (if enabled), or authenticate via SMS and wait 7 days (if pin enabled)"
    - beagle3 6y ago
      https://github.com/B16f00t/whapa https://github.com/B16f00t/whapa (among other tools) appears to download it from Google without requiring any key from facebook or a rooted device. I haven't tried this specific tool yet (or others recently) but it was definitely possible in the past without requiring any key from FB/WA.
    - keyme 6y ago
      You can extract it yourself. https://github.com/YuriCosta/WhatsApp-GD-Extractor-Multithread https://github.com/YuriCosta/WhatsApp-GD-Extractor-Multithre... I do not vouch for this repo, but it gets the job done. The only creds required are your Google account creds. No per-user whatsapp keys necessary.
      - FiloSottile 6y ago
        That's disappointing, thank you for the link.
  - 6y ago
moepstar 6y ago
This is something i don't understand (at least for me/my use case): Are historic chats that important to have them backed up? To me, if there's anything of value, i'll save it via other means...
- greatgib 6y ago
  For me, chat history has a huge value. How many times things looks like meaningless when they are said but have a lot of values at a later date? For example, sometimes you wonder, "when was it that time when XXX event happened". Or "I remember that one day someone told me that he had the same problem as me, but who was it and what was his solution?" Otherwise, we are used to share thousands of links and snippets with my friends that we usually discuss. A lot of time, after a very long time (sometimes years), for some reason we remember that something or link about a topic was discussed long time ago, and then it is convenient to look into the history with keywords to find back the links and what was said at that time!
  - Aerroon 6y ago
    Sure, but wouldn't you want to have control over these backups yourself? Not only do you get increased privacy from it, you also won't be in for a nasty surprise when the service decides to remove old logs/stop doing business.
    - Erlich_Bachman 6y ago
      An average user doesn't commonly want to have control over anything themselves :P.
      - joe-collins 6y ago
        I disagree. They'd love to have control, but that control requires tech sophistication that none of the current tooling adequately elides.
        6y ago

londons_explore 6y ago

WhatsApps cloud backup on Android sits on Google drive by default. It is encrypted with a per user key known to WhatsApp. That means for a third party to access the chats, they need Google to hand over the data, and Facebook to hand over the key. The logical next step to add would be for Google to additionally encrypt the data with the users logon password or something derived from it. Google won't do this anytime soon for business reasons.

garmaine 6y ago
> That means for a third party to access the chats, they need Google to hand over the data, and Facebook to hand over the key. National intelligence agencies (plural) would already have both.
- londons_explore 6y ago
  True, but it still makes the attack surface much smaller - employees of neither company could steal your data. Your data is now protected by the intersection of the companies privacy policies rather than the union of them.
  - beagle3 6y ago
    It used to be that way. But then, one day, Google announced that WhatsApp backups (a) no longer count towards your quota, and (b) are no longer encrypted. There are two beneficiaries of this change: 1) Intelligence and law enforcement agencies, which now have direct access to WhatsApp history for everyone who uses cloud backup (99.9% of users, if not 100%), without the need to 0day any specific phones, risk detection, or even have those phones on except occasionally. 2) Google, who can now mine your private conversations, metadata, etc. (At a tiny storage cost for Google, for which they are likely compensated by the NSA)
paranoidrobot 6y ago
> encrypt the data with the users logon password or something derived from it This leads to inability to restore a backup if you forget your password and need to reset it. That's going to lead to screams/tears from a lot of folks who don't realise those implications.
sdflhasjd 6y ago
WhatsApp backups are a bit of an anti-feature, as I found out while trying to ditch the app after the recent policy update. 1) The backup can only be made to Google drive, you cannot create a manual backup to a location of your chosing 2) The backup is created in a secret folder that cannot be accessed by the user 3) The backup is deleted if you delete your account. (not much of a backup, eh?) 4) You can only create per-channel exports, but this won't export the entire chat, it will export up to ~12MB of recent media, and ignore the rest, silently. WhatsApp would only share the last 40 messages of a 4-year-old chat because the last few messages contained a few images.
- londons_explore 6y ago
  I believe there is still an (undocumented, unofficial) way to backup to the SD card. The backup is still encrypted tho, and can only be restored to the same whatsapp account as created it.
- ycombinete 6y ago
  Interesting. I just created a 900MB backup of a chat history, on my iOS WhatsApp, that appears to have all messages and all data.
  - tinus_hn 6y ago
    Being an iOS device it probably doesn’t ‘backup’ to Google Drive so this story may not apply
    - ycombinete 6y ago
      yeah, on ios whatsapp backs up the data to icloud
- jsmith99 6y ago
  I can't find any source for this 12MB limit? Backups I've restored (Android) seen to contain all media although I haven't checked in detail.
keyme 6y ago
I've posted this here before. > It is encrypted with a per user key known to WhatsApp. This is no longer true! For a few years now. The backup is stored on Google Drive in plain text. https://faq.whatsapp.com/android/chats/about-google-drive-backups/?lang=fb https://faq.whatsapp.com/android/chats/about-google-drive-ba...
- FiloSottile 6y ago
  That page doesn't say that, and "tied to the phone number" sounds like they will only give you the key if you can authenticate via SMS. Do you have a better cite or did you check directly recently?
  - londons_explore 6y ago
    > authenticate via SMS It's now "authenticate via SMS and pin (if enabled), or authenticate via SMS and wait 7 days (if pin enabled)"
  - beagle3 6y ago
    https://github.com/B16f00t/whapa https://github.com/B16f00t/whapa (among other tools) appears to download it from Google without requiring any key from facebook or a rooted device. I haven't tried this specific tool yet (or others recently) but it was definitely possible in the past without requiring any key from FB/WA.
  - keyme 6y ago
    You can extract it yourself. https://github.com/YuriCosta/WhatsApp-GD-Extractor-Multithread https://github.com/YuriCosta/WhatsApp-GD-Extractor-Multithre... I do not vouch for this repo, but it gets the job done. The only creds required are your Google account creds. No per-user whatsapp keys necessary.
    - FiloSottile 6y ago
      That's disappointing, thank you for the link.
- 6y ago

moepstar 6y ago

This is something i don't understand (at least for me/my use case): Are historic chats that important to have them backed up? To me, if there's anything of value, i'll save it via other means...

greatgib 6y ago
For me, chat history has a huge value. How many times things looks like meaningless when they are said but have a lot of values at a later date? For example, sometimes you wonder, "when was it that time when XXX event happened". Or "I remember that one day someone told me that he had the same problem as me, but who was it and what was his solution?" Otherwise, we are used to share thousands of links and snippets with my friends that we usually discuss. A lot of time, after a very long time (sometimes years), for some reason we remember that something or link about a topic was discussed long time ago, and then it is convenient to look into the history with keywords to find back the links and what was said at that time!
- Aerroon 6y ago
  Sure, but wouldn't you want to have control over these backups yourself? Not only do you get increased privacy from it, you also won't be in for a nasty surprise when the service decides to remove old logs/stop doing business.
  - Erlich_Bachman 6y ago
    An average user doesn't commonly want to have control over anything themselves :P.
    - joe-collins 6y ago
      I disagree. They'd love to have control, but that control requires tech sophistication that none of the current tooling adequately elides.
      - 6y ago