Mastodawn

@Mer__edith
Can we get a comment on this?

1) The default Signal setting to show message contents in push notifications seems... bad, assuming this article is accurate.
2) Does changing the in-Signal-app setting for Notification Content indeed prevent notifications from being stored anywhere, which by default contains incoming message bodies.

@Mer__edith
On the macOS side of things, we have confirmation that Signal notification contents get stored, even for disappearing messages

iOS sadly offers less visibility into what's going on. But the FBI probably appreciates that it's happening there too.

The default notification setting for Signal (on both iOS and macOS) ensures that potentially sensitive information leaks out of the Signal app. This is unfortunate.

When Disappearing Messages Don't Disappear

@Mer__edith
From elsewhere on the interwebs:

@Mer__edith
From a worse place on the interwebs.
Implying:
Signal message content being present in Apple Notifications database even after Signal itself is deleted is apparently expected and fine.

Signal message content being present for self-deleting messages is not (in their minds).

🤔

@Mer__edith
Note the precise use of deleted messages here. When you uninstall the Signal app, that doesn't flag it's messages as "deleted" so that Apple can remove them from the notifications database. (If Apple would ever comply with Signal's demands. iOS (and macOS) don't have such a feature)

I don't think that this behavior maps up with users' expectations of the software. And for Signal to ship knowingly with a default setting that violates user expectations for a secure messaging app, well, I don't like it.

Don't get me wrong, I love the Signal product, and I've donated financially to it multiple times. But this ain't right.

Will Dormann Apr 22

@Mer__edith
This apparently is addressed as CVE-2026-28950

What is unclear is what is meant by

Notifications marked for deletion could be unexpectedly retained on the device

Is this only disappearing messages in Signal? Or any notification that has been acknowledged? 🤔

Will Dormann Apr 23

@Mer__edith
Apparently it applies to deleted apps as well.

Will Dormann Apr 23

@Mer__edith
What's unclear is what happens when Signal is not deleted? Or self-deleting messages aren't used. 😂

People shouldn't have to wonder.

Alesandro Ortiz 🇵🇷🏳️‍🌈Apr 15

@wdormann @Mer__edith FWIW, at least some Android flavors have Notification History feature too. e.g. my Samsung phones have had it for years.

In UI it only shows 24 hours of history and doesn't show uninstalled apps, but not sure if older or uninstalled app notifications are actually deleted behind the scenes.

I agree Signal should have No Content by default. Also needs clear warning about risks when relaxing settings.

Alesandro Ortiz 🇵🇷🏳️‍🌈Apr 15

@wdormann Now I'm wondering how Windows behaves here too. Can't test now but IIRC it does store notifs for at least a few days.

@wdormann @Mer__edith

#enshittification

Kobold Apr 15

Awkward Turing Apr 15

@wdormann that's exactly what I was worried about. It suggests that whatever the/an app sends to the notification service gets stored, since OS notification settings would most likely apply only after and not before storage. That's .. creepy but not too surprising.

Thanks for raising awareness!

@AwkwardTuring
It's easy to fix. It's just somewhat surprising to me that Signal ships with obviously insecure defaults.

Awkward Turing Apr 15

@wdormann it is. I'm only worried about all the apps (or users for that matter) that rely on OS' built-in notification settings instead of more granular in-app-settings.

Again: not too surprising but leaves a sour taste nonetheless.

Fritz Adalis Apr 15

@wdormann @Mer__edith
My expectation as a user would be that the os stores notifications until they're read, unless I make a change otherwise. It seems like they're stored 'forever'.

@FritzAdalis @Mer__edith
Right. And especially given the black box nature of the iOS platform, it would be nice for some official statements from the Apple and/or Signal side of things.

Nobody wants to be surprised by things like this.

buherator Apr 15

@wdormann As I understand they "knowing why" (as of now) doesn't imply this was *expected* behavior before.

I'd compare the persistent (not self-deleting) messages dilemma to secure deletion: below the next architectural boundary you can't really decide what's happening to your data ("were the bits of that file really deleted from the disk?"), but in special cases you take extra steps to prevent leaks ("let's overwrite a bunch of times, hopefully it helps").

@Mer__edith

@buherator @Mer__edith

A path that would make me feel more comfortable would be:

We've changed the default setting in Signal to not put message bodies in the (external-to-Signal) notifications database. At least until the dust has settled.

But no, the battle that is being chosen is:
We are pleading with Apple to have self-deleting messages not be permanently retained in the notifications database.

I get that security vs. usability are usually at odds with each other. But I suppose I'd like a bit more transparency here.

buherator Apr 15

@wdormann I'd agree with that, but I don't know what level of control apps have on mobile.

@Mer__edith

@buherator @Mer__edith
Signal has 100% control of this.
The screenshot is from the Signal iOS app settings.

Signal can't play the "We can't do anything about this" card. It's their default setting that is less secure than it should be.

Timo P.Apr 9

@wdormann @Mer__edith I was unaware notifications on iOS were stored in an on-device database even after they had been dismissed. That seems like an inefficient waste of storage - does anybody have a link to some Apple docs providing context about this database?

@tdpsk @Mer__edith
The problem is that such content is not included in unencrypted backups. So we mortals can't even confirm this, as we don't have access to full-device exploit tools such as Cellebrite.

Timo P.Apr 10

@wdormann @Mer__edith from what I understand it was forensically recounstructed from storage, the database itself is non-persistent (on the software layer). So something Apple could solve in a future update, e.g. by regularly properly wiping that part of storage.

Will Dormann Apr 10

@tdpsk @Mer__edith
Right, why is this data persistent at all?

Jason Petersen (he)Apr 9

@wdormann @Mer__edith it should probably be changed but you also have to weigh this against how many people would try Signal, see that it lacks message previews, and go back to SMS.

Mary Branscombe Apr 9

@wdormann I mean, before 2025 did the average mainstream user have the US government in their threat model?

Randall Lee Apr 10

@marypcbuk @wdormann The government has always been a threat to any left of center activists. The right planned their insurrection on public Facebook groups without precautions.

⠠⠵ avuko Apr 9

@wdormann The default setting for the iPhone by the US company Apple is to pass messages through to their Notification functionality.

They could be retrieved by the FBI from the US company Apple's push notification database.

The US company Apple, not Signal, has a shoddy security model here.

PS: To any Apple fanboys who can't stand a single bad word about Apple, I'll block you permanently and happily if you even give a squeak.

#Apple #Signal #FBI #Fascism

Awkward Turing Apr 9

@wdormann what does that mean for any other app that pushes sensitive data as notifications? Wondering if disabling the notification rly disables the storing in the DB or just the display of it.

@AwkwardTuring
Right. That's the million dollar question.

Drew Mochak Apr 9

@wdormann The default setting is that you get notified when you receive a message, because most people want those.

@prism
The default setting is that you get notified with the message contents

craignicol Apr 9

@wdormann @mastodonmigration eh what?

On Android it just shows "you have a new message". Was this an Apple or a Signal decision?

Erwin Rossen 🔸Apr 9

@craignicol @wdormann @mastodonmigration On my Android it did show Name and message completely. Not sure if I have changed that setting myself in the past 8 years that I have been using Signal, or whether that is/was the default.

craignicol Apr 9

@erwinrossen @wdormann @mastodonmigration hmm. Entirely possible the default has changed

Daniel Fisher(lennybacon)Apr 9

@wdormann Looks different here. But it’s Most probably the „Preview“ -Thing that causes Information to leak (to the OS which persists it unsecure)

@lennybacon
The screenshot I shared is from the Signal app itself, in Settings.

Not iPhone-wide settings.

Daniel Fisher(lennybacon)Apr 9

@wdormann Thanks. Looks the same in the app to me.

Probably the same but configured from the opposite side of things.

Thomas Reed Apr 9

@wdormann @Viss It’s been a while since I installed Signal, but I have a vague memory that it may have reminded me to change that setting the first time I ran it.

@thomasareed @Viss
I don't believe you, as that setting (my screenshot) is within the Signal app itself.

As such, if they wanted a different default value, they would have just released the software with the preferred setting.

Thomas Reed Apr 9

@wdormann @Viss Okay, whatever. “I don’t believe you” is a pretty rude response, as it implies I’m lying and that nothing changed in the years since I installed it. I do distinctly remember some kind of warning about Signal notifications from somewhere, though, so this is most definitely NOT new news.

lazarus7 Apr 9

@wdormann switching my friends and family to signal was made easier because of settings like this. It behaves like a normal messaging app. None of them have a threat model that has them thinking of device seizure by law enforcement.