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.
jhalstead 1 minutes ago [-]
Fwiw, in my Signal app on Android this setting is in
Settings > Notifications > Messages > Show
chasil 34 minutes ago [-]
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?
alin23 7 minutes ago [-]
Not sure if it's exactly the same, but I had to add a When notification arrives with <message>, do <action> 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.
jhalstead 4 minutes ago [-]
On a Pixel, I can see some history by going to
Android > Notifications > Manage > Notification History
I don't know if that's what's being referred to in the article though.
chinathrow 12 minutes ago [-]
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.
arkon_hn 4 minutes ago [-]
If the notification has the data, then yes. It's trivial to create an app that listens to notifications; Samsung even has one themselves called NotiStar that replicates the notification history feature that Android normally has.
mnls 6 minutes ago [-]
People who NEED to hide their notifications from iOS have this already disabled.
They rest who "evaluate their threat models" can practice Spy-life-gymnastics by disabling it from Signal.
frizlab 46 minutes ago [-]
Aren’t notifications supposed to be encrypted for Signal?
shantara 38 minutes ago [-]
iOS stores the previously displayed notifications in an internal database, which was used to access the data. It’s outside of Signal’s control, they recommend disabling showing notification content in their settings to prevent this attack vector
makosdv 36 minutes ago [-]
You can choose what to show in the notification and there is an option to include the message, so I'm guessing that allowed some unencrypted incoming messages to be read.
frizlab 32 minutes ago [-]
Sibling comment explains. The notification does arrive encrypted and is decrypted by an app extension (by Signal), however, if the message preview is shown, it is stored unencrypted by iOS. It is that storage that is accessed.
butvacuum 30 minutes ago [-]
it seems iOS will drop previews into an unencrypted section. which, Is how I expected iOS notification previews to work without unlocking the phone
krisknez 21 minutes ago [-]
This kind of vulnerability is not tied to Signal but all apps which send notification.
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.
preinheimer 19 minutes ago [-]
This feels like it would run against the “I bought my device, I should control how it behaves” line of thinking.
etiam 3 minutes ago [-]
But it would be pretty well in line with the "I trust my contact with this communication, but only if they're not systematically misled to copy it to readily exploitable insecure storage" line of thinking.
Since the purposes of the program are pretty heavy on private communication, I'm inclined to think that takes precedence here, especially considering the consequences for dropping default message previews versus adding default reveal of supposedly private information.
kome 13 minutes ago [-]
smartphones in general runs against the “I bought my device, I should control how it behaves” line of thinking
i_am_proteus 27 minutes ago [-]
Reminder that no end-to-end encryption arrangement can do anything before encryption, or after decryption, at the endpoints.
windowliker 12 minutes ago [-]
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 several 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 some effort at the user end to fill in a few gaps.
kome 12 minutes ago [-]
signal is security theater, and a very bad user experience
Rendered at 12:34:28 GMT+0000 (Coordinated Universal Time) with Vercel.
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.
Settings > Notifications > Messages > Show
"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?
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.
Android > Notifications > Manage > Notification History
I don't know if that's what's being referred to in the article though.
They rest who "evaluate their threat models" can practice Spy-life-gymnastics by disabling it from Signal.
Since the purposes of the program are pretty heavy on private communication, I'm inclined to think that takes precedence here, especially considering the consequences for dropping default message previews versus adding default reveal of supposedly private information.
I've found several 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 some effort at the user end to fill in a few gaps.