Is my S9 running on Android 10?

[ColonelJay]

Is it possible after my girlfriend's phone has been hacked for her phone to say it's running on Android 10 when it isn't? If so what should she do? 

Also, how would an APK file be modified to corrupt the file aka Android security bug 8219321 and the master key vulnerability because my girlfriend's S9 has been hacked through WiFi and I don't know how this was done or can be corrected. On her open source license it refers to Apache when she hasn't put an APK file on the phone. How could APK file have got onto the phone. Thanks. 

[BandOfBrothers]

Out of the box Samsung phone's are set up to reject files from unknown sources so unless she's bypassed this in the phone's settings an apk file shouldn't have been able to be downloaded onto the phone.

Has anyone been able to have hands on with the phone which is the usual source of something not being right.

The phone has a built-in in security scanning option as well as download able apps from the Playstore to run sweeps.

A Samsung Experience Store or Samsung Service Centre can take a look @ColonelJay 

And or factory reset the phone which may help but consider not using any back ups to restore information back onto the phone.

i.e start afresh.

[ColonelJay]

Thanks. Very helpful 👌