Threat Model Discrepancy: Google Password Manager leaks cleartext passwords via Task Switcher (Won't Fix) - Violates German BSI Standards
Hi everyone, Iβm a Cybersecurity student at HFU in Germany and recently submitted a vulnerability to the Google VRP regarding the Google Password Manager on Android (tested on Pixel 8, Android 16).
The Issue: When you view a cleartext password in the app and minimize it, the app fails to apply FLAG_SECURE or blur the background. When opening the "Recent Apps" (Task Switcher), the cleartext password is fully visible in the preview, even though the app actively overlays a "Enter your screen lock" biometric prompt in the foreground. It basically renders its own secondary biometric lock completely useless.
Google's Response: Google closed the report as Won't Fix (Intended Behavior). Their threat model assumes that if an attacker has physical access to an unlocked device, it's game over.
The BSI Discrepancy: What makes this interesting is that the German Federal Office for Information Security (BSI) recently published a study on Password Managers. In their Threat Model A02 ("Attacker has temporary access to the unlocked device"), they explicitly mandate that sensitive content MUST be protected from background snapshots/screenshots. So while Google says this is intended, national security guidelines classify this as a vulnerability. (For comparison: The iOS built-in password manager instantly blurs the screen when losing focus).
Here is my PoC screenshot:
https://drive.google.com/file/d/1PTGKRpyFj_jY9S76Jlo62mSCDJ3c6uLO/view?usp=sharing
https://drive.google.com/file/d/1nIJMQbM4R17EMt9f1Ffb4UmCPYY7-GXb/view?usp=sharing
What are your thoughts on this? Should password managers protect against shoulder surfing via the Task Switcher, or is Google right to rely solely on the OS lockscreen?
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