MS Paint and Photos inivisibly watermark even locally generated output with GUID
A security researcher discovered that Microsoft's Paint and Photos apps embed invisible GUID watermarks in images generated by local AI models. The analysis involved reverse-engineering local ONNX model files found within the Windows application directory.
Why it matters
This reveals how major tech companies are implementing provenance and tracking mechanisms in local AI tools, raising questions about user privacy and data traceability.
This research started with my curiosity about Paint. I recently had some success looking into less-explored Windows features like UCPD , WHESCVC , and I have long known that Microsoft added a bunch of AI features into the Paint app. I do not know if anyone actually uses Paint + AI to generate images, but I wanted to see how exactly the image generation works.
Before I started, I expected that it simply called a remote API to do the image generation. However, after I set up Binary Ninja MCP with Codex and started the analysis, I soon realized that Microsoft actually shipped local models in Windows as part of Copilot.
The Paint App is sitting in the following path (yes, they are all Windows Apps now):
C:\Program Files\WindowsApps\Microsoft.Paint_11.2605.71.0_x64__8wekyb3d8bbwe\PaintApp\ And there are four apparent model files with the .onnxe extension:
Get smarter about the news
Sign up free for a feed built around what you actually care about, Dive Deeper research on any story, and the full text of every article.
Create free accountAlready have an account? Sign in