Your Windows screenshots could be sharing info you cropped out

The built-in screenshot tool in Windows has been given a major upgrade in the last few years. Initially the Snipping Tool was part of the PowerToys collection, before getting a major boost and becoming the default screenshot interface in Windows 10 and 11. But it seems like the current version of the tool might be sharing a lot more than intended, albeit in highly specific scenarios.

A few days ago security researchers found that screenshots taken and cropped on Google Pixel phones could be analyzed with specialized recovery tools, making at least some of the cropped portion of the images visible again. This “Acropalypse” caused users to take a good, hard look at other default screenshot tools. As Bleeping Computer reports, several researchers found similar issues with the Windows 11 Snipping Tool and the older Snip & Sketch interface for the same function.

Can confirm.Easy test:1. Copy an image (to have a backup)2. Open one with Snipping tool3. Crop it to make it much smaller4. Click the Save icon5. Compare file sizes of cropped and original6. Wonder about the world that you live in https://t.co/2V3totEqw6 pic.twitter.com/g19MTxlzN1— Will Dormann (@wdormann) March 21, 2023

The issue stems from the way in which the tools save PNG files, specifically the way they overwrite files with the same name after an initial file has already been saved. As it turns out, the screenshot tools are incorrectly truncating the saved file, possibly leaving portions of the original, uncropped image behind. Recovery tools can be used to make part of the original image visible again. Full, perfect recovery of the original file doesn’t appear to be possible at this time, but corrupted versions of the full-sized file could still show enough to recover sensitive text or images.

The issue gets into some pretty heavy technical jargon. But if you need a Star Trek-style metaphor, it’s the difference between physically cutting out a photo from a newspaper with scissors, or merely covering it up with a sticker. In the latter example, the photo is still there and possibly damaged, and with careful work you can still see it.

There is some good news. While it’s fairly easy to expand a cropped image back to its original dimensions, that doesn’t automatically mean all the cropped data is restored. And the recovery method only works after a fairly lengthy sequence of events: The image has to be saved with the Snipping Tool (or Snip & Sketch), then cropped within the tool’s interface, then saved again to the same file with the same filename. It doesn’t appear to work if you simply press Print Screen and crop a full screenshot, then save that file or paste it into another program.

Microsoft representatives have responded to stories posted on multiple technology sites, indicating that the company is aware of the problem and working on a solution.

Security, Windows