Live data from Hacker News

FBI used iPhone notification data to retrieve deleted Signal messages

9to5mac.com

11–20 of 322 posts

Re: FBI used iPhone notification data to retrieve deleted Signal messages

#13

There needs to be a bit more "group chat" control in Signal messages, wherein you could enforce certain settings for certain chats regardless of the phone settings. You could have group chats that would enforce not showing more information in the notifications, while others would still allow it.

This feels like it would run against the “I bought my device, I should control how it behaves” line of thinking.

Re: FBI used iPhone notification data to retrieve deleted Signal messages

#14
Settings > Notifications > Notification Content > Show: "Name Only" or "No Name or Content"

I've had this enabled to prevent sensitive messages from appearing in full whilst showing someone something on my phone, but I guess this is an added benefit as well.

Re: FBI used iPhone notification data to retrieve deleted Signal messages

#15

There needs to be a bit more "group chat" control in Signal messages, wherein you could enforce certain settings for certain chats regardless of the phone settings. You could have group chats that would enforce not showing more information in the notifications, while others would still allow it.

This feels like it would run against the “I bought my device, I should control how it behaves” line of thinking.

smartphones in general runs against the “I bought my device, I should control how it behaves” line of thinking

Re: FBI used iPhone notification data to retrieve deleted Signal messages

#16

Reminder that no end-to-end encryption arrangement can do anything before encryption, or after decryption, at the endpoints.

Right. It's purely a protection against MitM snooping. The app has to have the messages in plaintext to display to you via whatever mechanism the OS uses. Seems obvious, but also not, at the same time.

I've found other ways Signal can leak information, even with disappearing messages. It's not the total install-and-be-done privacy screen that some people think it is, and requires a little effort at the user end to fill in a few gaps.

Re: FBI used iPhone notification data to retrieve deleted Signal messages

#18
On Android, when I use WhatsApp and have notifications for groups turned off, I can still see that they arrive briefly and then get removed (the icon top left vanishes). I wonder often, if this is a way to push all group message content into an unencrypted data trace as well - for the same use case.

Re: FBI used iPhone notification data to retrieve deleted Signal messages

#19
post #7

First, a critical setting for Signal users: "Signal’s settings include an option that prevents the actual message content from being previewed in notifications. However, it appears the defendant did not have that setting enabled, which, in turn, seemingly allowed the system to store the content in the database." Second, how can I see this notification history?

Not sure if it's exactly the same, but I had to add a When notification arrives with , do event trigger in my Crank macOS app (https://lowtechguys.com/crank) so I can show you how to do it on macOS:

      HOURS=6
      EPOCH_DIFF=978307200
      SINCE=$(echo "$(date +%s) - $EPOCH_DIFF - $HOURS * 3600" | bc)

      sqlite3 ~/Library/Group\ Containers/group.com.apple.usernoted/db2/db \
        "SELECT r.delivered_date, COALESCE(a.identifier, 'unknown'), hex(r.data)
        FROM record r
        LEFT JOIN app a ON r.app_id = a.app_id
        WHERE r.delivered_date > $SINCE
        ORDER BY r.delivered_date ASC;" \
      | while IFS='|' read -r cfdate bundle hexdata; do
          date -r $(echo "$cfdate + $EPOCH_DIFF" | bc | cut -d. -f1) '+%Y-%m-%d %H:%M:%S'
          echo "  app: $bundle"
          echo "$hexdata" | xxd -r -p > /tmp/notif.plist
          plutil -p /tmp/notif.plist 2>/dev/null \
            | grep -E '"(titl|title|subt|subtitle|body|message)"' \
            | sed 's/^  */  /'
          echo "---"
      done
Basically, notifications are in an sqlite db at ~/Library/Group Containers/group.com.apple.usernoted/db2/db and are stored as plist blobs.

In recent years, filesystem paths for system services have started to converge for both macOS and iOS so I'm thinking with jailbreak you could get read access to that database and get the same data out of it.

Post reply on HN