this post was submitted on 07 Apr 2026
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187
Signal messages retrieved from iOS notification, as seen in Prairieland federal trial (infosec.pub)
submitted 17 hours ago by frocalannifo@fedia.io to c/technology@lemmy.world
47 comments fedilink hide all child comments
 

TLDR: signal content in Apple notification can be retrieved even after signal app deletion.

I saw from this reddit thread: Signal messages retrieved from iPhone after uninstalling app. : signal

Referencing this news article: Pretti Killing May Affect ICE Prairieland "Antifa Cell" Terrorism Trial

The mention of signal is in court documents here: March 10: Federal Trial Day 12 - Support the Prairieland Defendants

Signal chat evidence from Sharp’s device (Exhibit 158):
Messages were recovered from Sharp’s phone through Apple’s internal notification storage — Signal had been removed, but incoming notifications were preserved in internal memory. Only incoming messages were captured (no outgoing).

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[–] scytale@piefed.zip 45 points 16 hours ago* (last edited 15 hours ago) (3 children)

I learned about this a couple of months ago and I've since disabled previews in notifications. It's unfortunately the nature of how notifications are delivered to you. You should be fine by disabling message previews in your notification settings.

[–] in_my_honest_opinion@piefed.social 32 points 16 hours ago (1 children)
[–] spectrums_coherence@piefed.social 10 points 13 hours ago (2 children)

I think on android, signal do not use Google's push notification. They simple send a dummy push, and the signal app wakes up to retrive the latest message directly from signal server.

So Google never have your notification content. I am not sure if they do the same on iOS.

That being said if your attack model includes people reading your notification lock screen, then you should disable showing signal notification.

[–] 0_o7@lemmy.dbzer0.com 1 points 27 minutes ago (1 children)

I think on android, signal do not use Google's push notification.

Source?

[–] in_my_honest_opinion@piefed.social 7 points 11 hours ago

The message preview notification is handled similarly in IOS and Android. The issue isn't people seeing the notification, it's that the content of the message being passed to the phone's launcher. Which is unencrypted.

[–] eleijeep@piefed.social 12 points 16 hours ago (1 children)

Does that actually prevent the app from sending the content through Apple’s servers or does it just prevent iOS from showing it in the notification area?

[–] Bazoogle@lemmy.world 6 points 15 hours ago

The only way apple is seeing it is when the notification is displayed. It only sees the contents of the notification itself. So it would still see who sent you a message, but it wouldn't say what it was

[–] Bazoogle@lemmy.world 10 points 15 hours ago* (last edited 15 hours ago) (1 children)

It's worth noting apps can avoid this on Android: https://tuta.com/blog/google-push-alternative#alternatives-to-google-push

Any FDroid app cannot use Firebase for push notifications since it's proprietary: https://forum.f-droid.org/t/firebase-allowed-in-fdroid-apps/7540

[–] WhyJiffie@sh.itjust.works 1 points 13 hours ago* (last edited 13 hours ago)

It's not because of push notifications. the message is not sent to firebase, just a signal that the app should do a refresh.

It's because the system saves the notifications apps posted to the notification menu.

but yes. don't use firebase push notifications if you can avoid it. use a unifiedpush based system. base signal app does not support it, only molly. there are some difficulties though with that that are unique to signal.