The Wi-Fi settings that is being used to break into your financial accounts is called “Auto-Join” and it is used to automatically connect iPhones to public hotspots and Wi-Fi networks at bars, restaurants, coffee shops, bookshops, and more. By default, these two settings are setup to automatically have your phone connect to a network or hotspot practically placing a red bullseye target around your phone.
“The biggest threat to free Wi-Fi security is the ability for the hacker to position himself between you and the connection point. So instead of talking directly with the hotspot, you’re sending your information to the hacker, who then relays it on. While working in this setup, the hacker has access to every piece of information you’re sending out on the Internet: important emails, credit card information, and even security credentials to your business network. Once the hacker has that information, he can — at his leisure — access your systems as if he were you.”-Kaspersky
If you do connect to a mobile network or a hotspot that you don’t plan on connecting with again, you can remove it from your phone by going to Settings > Wi-Fi and tapping Edit in the upper right corner. Networks you can delete will have a red circle with a white dash in the middle on the left side of the display. Tap that symbol on the networks you wish to delete from your phone and tap the red box that says “Delete.” When you’re finished, tap the Done button in the upper right corner of the screen.
Also be careful of Wi-Fi networks that look similar to the name of a legitimate restaurant or a hotel but with minor spelling errors. These could be fake networks setup by criminals who hope that you’ll connect your device to it and reveal personal data that can be used to break into your financial apps.
