Hey I can shed light on this. It’s the iCloud keychain. Disabling the keychain doesn’t delete existing entries. There is no way to modify the keychain on iOS (you can on Mac). Lots of apps store sign on data in the keychain for obvious reasons.

It would be really great to have a keychain section in iOS’s settings, like Keychain Access on Mac. The dev can build in-app functionality to delete keys from the keychain, but there’s not a huge incentive to.

Keychain storage doesn’t let FB track you, just store sign on info, keys, and the like. It’s not able to execute arbitrary code, it’s an encrypted place to store login info that Apple syncs between your devices.

Use them via Safari if you don’t want this (then your logins are saved & synced in Safaris keychain.)

It's not specific to iCloud Keychain--it applies to on-device Keychain on iOS devices, too, even if you don't use iCloud. Any developer can store data there with no way for the user to know or see what it's saving, and it's shared among all apps from the same developer. Keychain is quite a misnomer here--it's really "store any (short) data you want on a user's device without them ever being able to see or remove it". It transfers when you restore backups on new devices, too, even if you haven't had the developer's apps installed in the last decade.

This is an issue because if you ever use an app by a company, uninstall all their apps, and then install one of the developer's apps years later, they can tell it's the same iOS profile (even restored on a different device), profile what you do across those apps/installs/decades, and associate any accounts you log in with. Essentially they can put a permanent cookie that you can't even see on your iOS profile that's shared between their apps. If you use iCloud Keychain, they can probably profile you across all your devices regardless of whether you reset one.

Apple has said this isn't intended functionality and they were going to address the issue many years ago in iOS 10.3 by removing Keychain data when the last app from a developer was uninstalled [1], but they got cold feet. If I recall correctly, the reason was that some app developers were relying on this unintended functionality to ensure free trials couldn't be used more than once. Apple was going to introduce a service that could store only 2 bits of data to enable that use case and then revisit Keychain deletion when the last app from a developer is uninstalled, but it appears they haven't.

It would be great if they'd finally fix this.

[1] https://developer.apple.com/forums/thread/72271

This is also used heavily for abuse / spam / fraud prevention.

If you detect that a user is abusing your service, the ability to put a permanent cookie on their device is very useful.

This isn't effective against organized crime groups (they can just get Macs / use the web / whatever), but works well against your average troll or internet racist.

Still tracking, but a very different kind of tracking.

The "store 2 bits of information" approach Apple was moving exploring would solve at least a lot of that case. You could effectively store 3 pieces of information: 00 = default state, 01 = used free trial, 10 = banned, 11 = something else the developer wants to store about the iOS profile. You don't need to be able to uniquely identify it to ban it.

You’re right, I could have specified that even if you don’t use iCloud you have a keychain on iOS

> Keychain storage doesn’t let FB track you

It sure lets app developers identify me across app deletions and reinstalls!

I'm also not sure why Apple has kept this loophole open for so long when they are otherwise so focused on making sure user tracking across reinstalls is so hard (e.g. by making APNs tokens change after a reinstall, which used to not be the case as well, restricting access to read the device MAC address and other permanent identifiers etc).

You can theoretically do that, but that's against app store regulations. I'd imagine that logging out first, then deleting the app, should prevent the behavior because afterwards there's very little reason to have any sort of lingering keychain data. But at the end of the day, it's basically an honor system.

You can add/delete entries in the iOS keychain from the Passwords section.

And I am looking at my iPhone now and Meta does not store tracking data in the Keychain.

You certainly can not, here's some more info. Passwords and the keychain are separate items.

https://apple.stackexchange.com/questions/441112/how-can-i-r...

> Keychain storage doesn’t let FB track you

Are you serious? They literally know my previous accounts even after I DELETE the app, WIPE the iPhone, and login to the same iCloud account on ANOTHER iPhone.

They do this by storing some data. They can store data about anything else. How can be sure if we can't even LOOK at that data?

I only caught this because of the visible symptoms they CHOSE to show us: The list of previous logins.

This is nuts. There should be a grand total of zero files on my personal computing device that I cannot remove (no matter the consequences).

This seems fundamentally at odds with Apple's philosophy that they're providing you a rented appliance they control and which you have temporary access to.

I'm sure you can remove most and/or all Mac OS files, but they're increasingly using trusted computing and even designing their own chips to increase the control they have over the devices (and correspondingly limit user control).

They sell this as a security feature these days, but the appliance model predates that and security is kind of just along for the ride.

I'm glad to see that people feel strongly that they should have control over the files on their system. I'd like to see that help move us toward users having full control over their computers.

You can remove every file on your Mac.

And there are no eternal tracking cookies for Safari even first party ones are deleted every week.

then you have chosen the wrong platform. Just be grateful that the mighty apple even deems you worthy of having files

Android's security was way worse for years. How long did they even take before having granular permissions or a Privacy Report, if they do now at all?

uhm, they had different permissions granularized, in some ways worse than apple, some ways better.

but i was not talking security

It’s stored in your keychain.

Disabling the iCloud keychain doesn’t clear your local copy.

> Every attempt to talk about this gets ignored or buried (maybe by people who want this ""feature"" to be kept quiet) so I will take every opportunity on existing discussions about Facebook to bring it up:

Or maybe this happens because it's completely off-topic here and has nothing what-so-ever to do with WhatsApp?

Most of your other messages seem similarly off-topic: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...

Not only that, people have already answered your question in a previous thread.

It's less of a "question" and more of a "WHY THE FUCK is this even a thing???" and why aren't people giving FB/Apple hell for this??

There was a popular post just a few hours ago about Filezilla (whatever that is) containing adware in the default download.

This is a FAR more grave violation of privacy than anything so far — Tracking people ACROSS reinstalls AND MULTIPLE PHONES!

Not sure why you are using this thread as technical support.

Or what tracking data you are referring to ie. is it cookies or local storage but either way you should maybe speak to Apple Support.

Yes iOS apps can store local data and if you're unhappy about it then just delete or reinstall the app.

> just delete or reinstall the app.

Well, that doesn't delete all local data. That's exactly the problem!

> WHY does Apple, parading around as a pompous paragon of privacy, even allow this crap?

Good alliteration.

Apple doesn’t enforce what the app does with app data. Apple makes sure that if the app uses a platform API that is sensitive, it gets your opt-in (or prohibits the use of the API altogether). Apple makes sure that the app publishes a privacy nutrition label. But what the app does inside with whatever data you choose to give it, that’s up to the app.

If you voluntarily choose to give data to the app, what the app does with it is your problem. Apple just tries to make sure the app can’t take data that you haven’t chosen to give it.

That would be a nice solution, but there is no "allow app to persist data beyond deletion/reinstall" user-grantable permission on iOS.

There is no indication whatsoever that an app will leave behind an Eternal Cookie on my device, nor am I given a chance to prevent it.