Google Pixel Privacy nightmare: redacted or cropped screenshots may be recovered (partially)
Google Pixel owners who have used the built-in screenshot functionality and uploaded some of the screenshots to the Internet face a potential privacy disaster. Due to the way redacted or cropped screenshots are saved on Pixel devices, it is possible to recover the original unredacted image.
Named Aprocalypse by security researcher Simon Aarons, it is a serious issue that could lead to personal information being exposed on the Internet. To name a few examples: a screenshot of a credit card with a redacted number could reveal the number, a user who cropped an image to hide parts of it, could find that image being restored to full, and a user who published a screenshot with redacted address information could discover that the address may be revealed after all.
A demo site is available already that demonstrates the image recovery functionality. It seems to work with all recent Pixel devices, from the latest Pixel 7 Pro to Pixel 3. There is also an option to set a custom resolution for the image, which may then work with other Pixel devices as well.
Anyone with access to a Pixel screenshot that has been cropped or redacted may use the demo site to try and recover it. All image processing is done client side, according to the developers of the demo site.
Pixel device owners may use it to find out if their screenshots are affected by the issue. Here is a sample file that shows how the recovery works. Download it from this location and select Pixel 6a as the device.
A blog post on David Buchanan's blog provides details on the vulnerability, which is tracked as CVE-2023-21036. Aarons and Buchanan discovered that Google Pixel devices were overwriting cropped or redacted screenshots on the mobile devices with the new version, but not touching the "rest of the original file". This means, that the data is still on the device, and that it could potentially be restored.
The blog post is technical in nature, but it provides insight on how the issue was discovered and how it can be exploited. Without going into too many details, all that is required to detect if original image data is still available is to run basic checks on the image.
David Buchanan mentions that he wrote a simple script to parse all of his messages with screenshots on Discord to find out if any of them were vulnerable. Turns out, many were vulnerable, but most did not reveal private information. Still, one image, which showed the confirmation of an eBay order, could be restored to show the author's full postal address.
Google seems to be aware of the issue, but it is too early to tell how the company will react to it. Besides plugging the vulnerability, the company somehow has to address the elephant in the room: that fixing the vulnerability does not protect already uploaded or created images from being analyzed and recovered.
Not all images taken on Pixel devices and uploaded to the Internet are affected by the issue. Some Internet services and apps remove excess data from images before publishing the images. Images published on these services are not affected, as the original image is removed during the process by the service in question.
Still, depending on where an image was uploaded to or who it was shared with, it could lead to serious privacy issues for Pixel owners.
What Pixel owners may do
The very first thing is to analyze if there are potential privacy issues. If Google's tool was used to redact or crop images, and if these redacted or cropped bits contained sensitive information, and if the data was shared or uploaded, then there is a good chance that the issue affects the user.
The demo site may be used to test the images that could potentially leak private information. Getting the images off of the Internet is the hard part. Some images may be deleted, if the user has still control over them; this may work on personal websites, social media sites and forums. There is still the chance that the image was copied or downloaded by others, and there is little that one can do about that, unfortunately.
Closing Words
Affected Pixel owners may want to pull screenshots, which they edited on the device to redact or crop private information or sensitive parts and uploaded to a public place, from that place, if possible.
Now You: are you affected by the issue?
Thanks for the tip Martin.
It is for these kinds of posts that I follow GHacks.
What’s up with the generic comment, are you a bot?
2G?
Where on the planet is that still in use? I was forced to give up using my RAZRV3 years ago because 2G was phased out by AT&T.
Everywhere 3G has been turned off and you don’t have LTE coverage, and believe me there are many developed countries where this is the case and if it weren’t for 2G you wouldn’t even be able to make a phone call.
Maybe I missed it, but I don’t believe tha term “2G” is in the article. Perhaps you are referring to “AGM G2”??
@Martin
Your website has gone insane.
When I the post button I then saw my comment posted on a different article page. When I opened this article again, it is here.
@Tachy @Martin Brinkmann
” Your website has gone insane. ”
Same here. Has happened several times.
@Tachy,
@Martin P.,
For over two weeks now,
I’ve been seeing “Comments” posted by subscribers appearing in different, unrelated articles.
https://www.ghacks.net/windows-11-update-stuck-fixed-for-good/#comment-4572991
https://www.ghacks.net/windows-11-update-stuck-fixed-for-good/#comment-4572951
For the time being,
it would be better to specify the “article name and URL” at the beginning of the post.
@tachy a lot of non-phone devices with a sim in them rely on 2G, at least here in europe.
Usually things reporting usage or errors/alarms on something remote that does not get day to day inspection in person. They are out there in vast numbers doing important work. Reliable, good range. The low datarate is no problem at all in those cases.
3G is gone or on its last legs everywhere, but this stuff still has too much use to cancel.
Anyhow, interesting that they would put that in. I can see the point if you suspect a hostile 2G environment (amateur eavesdroppers with laptop, ranging up to professional grade MITM fake towers while “strangely” not getting the stronger crypto voip 4G because it is being jammed, and back down to something as old ‘stingray’ devices fallen into the wrong hands).
But does this also mean that they have handled and rolled out a fix for that nasty 4G ‘pwn by broadcast’ problem you reported earlier this year? I had 4G disabled due to that, on the off chance that some of the local criminals would buy some cheap chinese gear, download a working exploit and probe every phone in range all over town in the hope of getting into phones of the police.
>”While most may never be attacked in stingrays, it is still recommended to disable 2G cellular connections, especially since it does not have any downsides.”
The downside would be losing connectivity. I spend a lot of time way out in the countryside where there’s often no service or almost none. My network allows 2G, and I need it sometimes. I have an option on the phone to disable 2G, I may do that when I’m in the city and I have good 5G connectivity, but not out in the country.
I would imagine that the stingray exploits, like most of the bad things in this world, are probably things you will run into in the crowded big cities.
I stopped using it in a mobile (Wi-Fi line) environment, so I’m almost ignorant of the actual situation,
But the recent reality in Japan makes me realize that “the infrastructure of the web is nothing more than a papier-mâché fiction”.
https://www.ghacks.net/2023/08/17/google-chrome-to-enable-https-first-by-default-for-all-users/#comment-4572402
It is already beyond the scope of what an individual can do.
What we should be aware of is the reality that “governments and those in power want to control the world through the Web”, and efforts to counter (resist and prevent) such ambitions are necessary.
Why do you want people to disable the privacy features? Hmmmmm?
Now You: do you plan to keep the Ads privacy features enabled?
I’d like to tell you, but apparently if you make a post critical of Google, you get censored. * [Editor: removed, just try to bring your opinion across without attacking anyone]
@Martin
You website is still psychotic. Comments attach to random stories.
@Martin please do fix the comments, it’s completely insane commenting here! :[
@Martin
The comments are seriously messed up on gHacks now. These comments are mixed with the article at the below URL.
https://www.ghacks.net/2023/08/18/android-how-to-disable-2g-cellular-connections-to-improve-security/
And comments on other articles are from as far back as 2010.
What does this article has anything to do with all the comments on this article? LOL I think this Websuite is ran by ChatGPT. every article is messed up. Some older comments from 2015 shown up in recant articles, LOL
The picture captioned “Clearing the Android Auto’s cache might resolve the issue” is from Apple Carplay ;)
How about other things that matter:
Drop survival?
Screen toughness?
Degree of water and dust protection?