I have flashed an old Samsung phone with a custom ROM. The OS (and all the needed software) come from a website that "should" be safe, from users that "should" be trustworthy. Still, I like to be a bit paranoid when it comes to security.
And so, let's assume the mobile is now compromised, as a result of something nefarious in its ROM, and I connect it to my home WiFi (WPA2-secured). For our purposes, let's assume I'm not planning to enter any userID/passwords, and simply use the device to browse the Internet (not logging into anything).
If I installed and used a VPN on this device, would that reduce the risk to my network and the other devices?
I know that you're not supposed to use open public WiFi (I've also checked this question: How to use public WiFi safely?), but my situation made me wonder, if my fears are true, doesn't that mean a malicious user could, say, go to a public library that offers secure WiFi to their clients, to whom it provides the password, and connect to the network, compromising any other devices that use it?