[HN Gopher] Android wallpaper images can threaten privacy
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Android wallpaper images can threaten privacy
Author : Daniel_sk
Score : 98 points
Date : 2021-10-07 19:32 UTC (3 hours ago)
(HTM) web link (fingerprintjs.com)
(TXT) w3m dump (fingerprintjs.com)
| no_time wrote:
| Interesting article but its rich as fuck coming from a company
| whose sole product is weaponizing the ever increasing scope of
| browsers against users
| basicplus2 wrote:
| I take the article as an advert to say 'use us to fingerprint
| people, we are always thinking of different ways to reliably
| finger people'
| bogwog wrote:
| Yeah I don't know how to interpret this article. Is it a
| warning to users about a new threat to privacy, or is it an
| announcement to customers about improved tracking capabilities
| in Android 12/a potential product update?
|
| Even if it's just some inbound marketing blog spam bullshit,
| why would a company whose business it is to violate and exploit
| privacy want to post an article that will attract people who
| are concerned about privacy?
| [deleted]
| zaik wrote:
| > This color extraction algorithm is basically a map from the set
| of all possible images to the RGB color space. The set is
| infinite and the RGB color space is limited by 2^24 combinations.
| Theoretically, this means every RGB combination is possible.
|
| I know this is missing the point of the article, but this is not
| how the pigeonhole principle works.
| vorejdajo wrote:
| It's not constant. I expect that people change wallpaper
| frequently.
| eric__cartman wrote:
| It's been more than a year since I last changed my wallpaper.
| bbarnett wrote:
| I've used the same wallpaper on every computing device I've
| owned, for the last 26 years.
| shadowgovt wrote:
| Unfortunately, constancy is irrelevant. If a malicious app is
| using this API to locate you, it can detect when your wallpaper
| changes and use its app_id (unchanged) plus wallpaper
| fingerprint (changed) to phone home with "Yo, this user's
| wallpaper thumprint is now Y."
| Daniel_sk wrote:
| I don't think an average person changes wallpapers frequently.
| MrDresden wrote:
| Android dev here. Still have the same default wallpaper as my
| Pixel 3 came with 3 years ago.
| gambiting wrote:
| Do they? I've had the same "live wave animation"(that looks
| like the PS3's XBM menu) for at least 5 years now and I don't
| see any reason to change it.
| ChrisArchitect wrote:
| _how_ am I being tracked from this? It takes pages to get to the
| point where supposedly the wallpaper color reduction could be
| unique enough ....but when is that going to be used to track me?
| Or rather, who is going to depend on that to track me across the
| device? Stretch no?
| [deleted]
| techrat wrote:
| Color theme is generated from Wallpaper.
|
| Color theme consists of at least 3 colors taken from the
| wallpaper.
|
| At least 3 unique colors is enough to make the user potentially
| uniquely identifiable, depending on how rare the color combos
| are.
|
| 224 (R8G8B8) combinations for every color times 3 colors means
| 272 combinations.
|
| And there are color samples taken from potentially two
| different wallpapers.
|
| Other apps have access to the colors picked for the theme
| generated from the wallpaper so they can theme themselves
| accordingly.
|
| This means an app can use your color theme (of 3 or 6 colors)
| as a nearly unique fingerprint. The odds of collision for
| smaller apps (sub 1 million downloads) are pretty damn low.
| healsdata wrote:
| It generates a unique fingerprint for your phone that can be
| used across apps without permissions. So if you have multiple
| apps using the same ad network SDK, each of them will get the
| same unique fingerprint for you and can tie your activity
| together. If you're logged into one of the apps, then your
| activity across all the apps can be tied to your login even
| when you change your wallpaper.
| izacus wrote:
| Most apps will skip all that and just ask you to login before
| working. Much easier and they get your email ;)
| jeroenhd wrote:
| Although this is an interesting, novel method, there are so many
| fingerprinting capable APIs in native code that I don't think
| this matters much.
|
| Many apps I use daily require internal storage permissions and a
| bunch of them drop random dotfiles with magical IDs in there.
| Xiaomi even dumps a world readable unique device ID on the
| emulated SD card. Not all apps require external storage
| permissions, but even then there's tons of APIs that can be used
| to fingerprint the device.
|
| Google is trying their absolute hardest to reduce the
| fingerprinting surface but as long as system APIs that work with
| user content like these exist, there will always be something to
| fingerprint users by. If everything else fails, you could just
| embed a webview that uses all the javascript stalking we've grown
| so accustomed to.
|
| It's sad but I don't think you can prevent native code from
| fingerprinting your device. The sandbox just isn't tight enough
| and users are too willing to give out permissions.
|
| I can see Google using a predefined set of colours in some update
| instead of the raw colour values to combat this, but that's only
| one of many ways apps abuse their users' devices. Unless app
| stores kick out apps that fingerprint devices, I don't think
| we'll see any non-fingerprinted devices any time soon.
| amatecha wrote:
| "trying their absolute hardest to reduce the fingerprinting
| surface"... for anyone else :)
| ignoramous wrote:
| Yes, they indeed are. Though, it could be argued that Google
| doesn't want anyone _else_ fingerprinting 3B+ Android users
| other than themselves. Most of their apps ( "gapps") are pre-
| installed with backdoor privileges that can bypass sandbox
| restrictions in-place for every other (non-OEM) app.
| magicalist wrote:
| > _Most of their apps ( "gapps") are pre-installed with
| backdoor privileges that can bypass sandbox restrictions
| in-place for every other (non-OEM) app_
|
| Hadn't heard about this. Like what?
| SeriousM wrote:
| Could fuchsia be the solution to this? It's a fresh start and
| no company is depending on any of its api. But I guess fuchsia
| is a flaw for its own because of google...
| bayindirh wrote:
| I would assume the opposite. Why a company which makes money
| from tracking users for many reasons develops an OS which
| prevents tracking?
|
| My guess is that it'd be an OS which would perform tasks
| Google needs to stay as Google better than Android, and
| Google may sell these capabilities to devs to further
| _enhance_ their bottom line.
| saurik wrote:
| > Unless app stores kick out apps that fingerprint devices, I
| don't think we'll see any non-fingerprinted devices any time
| soon.
|
| Talk about throwing out the baby with the bath water on making
| Apple and Google the equivalent of government with the ability
| to define the rules on all software that anyone can exist
| without even considering using actual government :(.
| bbarnett wrote:
| _Google is trying their absolute hardest to reduce the
| fingerprinting surface_
|
| Really? If true, it's so they will be the only source of such
| tracking info.
|
| Google is like the one eye, it never stops seeking, looking,
| tracking you.
| vineyardmike wrote:
| > If true, it's so they will be the only source of such
| tracking info.
|
| So... they're reducing their competition? Sounds anti-
| competitive. They wouldn't know anything about that though.
| gruez wrote:
| >Many apps I use daily require internal storage permissions and
| a bunch of them drop random dotfiles with magical IDs in there.
| Xiaomi even dumps a world readable unique device ID on the
| emulated SD card.
|
| They're fixing this with soon with scoped storage api.
| curiousgal wrote:
| I mean apps already have access to your device ID, no?
| Daniel_sk wrote:
| They don't - without special permissions on newer Android
| versions (10+). There is an ANDROID_ID but it's scoped to your
| application on Android 8.0+, reinstalling the same app signed
| with same key will give you the same key but it returns a
| different value in other apps. This way you can't use for
| cross-app tracking.
|
| https://developer.android.com/training/articles/user-data-id...
|
| https://developer.android.com/reference/android/provider/Set...
| judge2020 wrote:
| How does Google share logins between different apps then? Is
| there some shared keybag/storage location that only works for
| the developer's own apps (and is it scoped to the actual
| developer account, not one that different developers can
| collude to use together)?
| smitop wrote:
| Apps that have the same signing keys can share code and
| data: https://developer.android.com/studio/publish/app-
| signing#con...
| [deleted]
| Daniel_sk wrote:
| I am not sure what mechanism is Google using. But Android
| apps can talk to each other on the same device and you can
| restrict this to only applications that are signed with the
| same certificate (and this is guarded at the OS level).
| gruez wrote:
| >How does Google share logins between different apps then?
|
| google play services
| azurezyq wrote:
| It seems that you don't use Android. There's an account
| system apps can use in the os.
|
| Just checked mine, I can see Google, Facebook, Reddit and
| quite a lot others there
| ohazi wrote:
| Modern high-end phones use OLED displays. Save your battery and
| set your background to black.
| edoceo wrote:
| Picture of the family thanks. Gotta remember why I carry around
| this beeping shit box.
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(page generated 2021-10-07 23:00 UTC)