This is related to an issue called root-phishing or superuser-phishing. You can do this with the Windows admin password prompt, the MacOS prompt, or with Linux sudo, as long as you can run code from a user account or edit a single file. alias sudo='sudo ./somethingbad; sudo' I'm surprised you don't hear about this that often. There is no perfect solution, since any visual feedback the operating system can do to make…
There are many solutions. First is requiring un-catchable keyboard shortcut to enter the password. Something like "ctrl-alt-delete" for Windows (I'm not sure if it's un-catchable, but you got an idea) or even better some unused key like pause/break. User will be trained to press this shortcut and app can't replicate it, so user won't be tricked. Second is using fingerprint. iOS should just use fingerprint always inst…
For example, how do you handle compromise (I suspect fingerprint mills / printers are not ubiquitous just because there is no demand for fake fingerprints; technologically they should be easy to make). Also, do you really want a unique match every time you log in from different devices (e.g., work and home); etc., etc.
Sorry, fingerprint solution may be worse than the disease it is trying to cure.