Is it really possible to hack a WiFi password with which I never connected it before in a device?

Yes, it is possible to hack into wifi which you never connected to.

1. Use aircrack-ng tool which is powerfull and open source to hack wifi. It gives you many options with it's vatious commands that how you want to crack the wifi. You can also deauthenticate the connected users to that wifi and catch the re-establishment of the connection to find the password.
2. Use bruteforce method with the popular passwords list or build your custom passwords list using crunch tool. Aircrack-ng supports the bruteforce method with providing the password file. This method may take very long time to get the password.
3. Using WPS pin. This method will be very fast for non wps locked wifi. You just need to find out what is the wps pin for the router which is printed downside of the router. If you find out the pin than no matter how many times the wifi password changes, you can connect to the wifi. But it should be wps unlocked only. Many routers by default are unlocked. You can also bruteforce the wps pin if you cannot get to the router physically by using reaver tool.
4. The very easy one, try to convince owner of wifi to enter the password on your device and once connected you can go to routers settings page by serching on browser the gateway of connected wifi which will be written in the wifi settings of connected wifi. The credentials for the login to router's page can be find out by searching for the default username and password of that router model. If not changed than. If changed than you can connect that wifi to your laptop and from network settings you can find the security type and password of the wifi also.
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