Friday, October 1, 2021

iOS 15 Messages Bug Deletes Saved Photos

Juli Clover:

If you save a photo from a Messages thread and then go on to delete that thread, the next time an iCloud Backup is performed, the photo will disappear.

Even though the image is saved to your personal iCloud Photo Library, it appears to still be linked to the Messages app in iOS 15, and saving it does not persist through the deletion of the thread and an iCloud backup.

Aside from the data loss, this bug is concerning because I thought that the Messages, iCloud Photo Library, and iCloud Backup systems would be isolated from one another. iMessage threads are supposed to be end-to-end encrypted in iCloud, and they aren’t backed up if you have syncing enabled. Photos and iCloud Backup are not end-to-end encrypted. And photos in iCloud Photo Library don’t go into the iCloud Backup, anyway.

Secondly, is there something a third-party app could do using the PhotoKit API that would also trigger the bug? Or is it related to private APIs that Messages is using?

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Just a guess…maybe something related to the shared with you feature in iOS 15?

Your messages threads are not E2EE unless you have iCloud backups turned off.

They’re E2EE with the key stored in the backup. So, not secure, but my point is that it’s a different storage system.

Do you know what the name of it? CSAM bug. The cause of this reeks of something related to the hasty shutdown of CSAM functionality (because of the PR nightmare this undesirable feature caused for Apple).

(My guess is Joel is right — that this is a bug related to Shared With You, not CSAM.)

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