iPhone 15 Plus Hacked Accounts. Is my iPhone hacked by someone I know?

It's nearly impossible for your iPhone to be "hacked", but far more likely that someone has access to one or more of your accounts. If your passwords are being changed on accounts where you have two-factor authentication enabled, then someone likely has access to your phone or other trusted device when you are not around. Therefore, first make sure that you have physical control of your phone (at all times), iPads, and the computers that you use. Allowing family members to use your iOS devices, or to login to a laptop as you, are other possible ways that your accounts are being compromised.

Start by trying to take back a few things to try to break the cycle. Here are some suggestions to get started. I'm sure others may post additional suggestions:

General security:

• Use a password manager (https://support.apple.com/en-us/120758) to store all of your passwords and two-factor authentication codes
• Use two-factor authentication on every account
• When possible, do not use email or SMS for two-factor codes.
• Never reuse the same password for anything. Use a different password for every login and account.
• Use strong passwords or passphrases. They need to be long and unguessable by anyone.
• Never store your passwords in an unencrypted file such as Word or Excel
• Never share iPhone or iPad devices. An iPhone is a personal device, and the security is not intended to be used by others. Allowing others access to your iOS device gives them access to a "trusted device" to your Apple Account as well as most other methods of two-factor authentication (SMS, email, TOTP app, push, etc.).
• Never share computer accounts (not even with a family member). Every person in a household needs their own login and password.
• Never share Apple Accounts with others or let someone else use your Apple Account on their device
• Learn about cybersecurity and how to avoid phishing and social engineering (Recognize and avoid social engineering schemes including phishing messages, phony support calls, and other scams - Apple Support

On your iPhone(s) and iPad(s):

• Change you iPhone's passcode: Settings > Face ID & Passcodes > Change Passcode (do not use anything that someone can guess).
• Check that there are not alternate appearances set up on your iPhone at Settings > Face ID & Passcodes.
• Enable: Settings > Face ID & Passcodes > Require Attention for Face ID
• Review: Settings > Apps > Messages > Send & Receive. The list of accounts that can receive messages should only include the phone number of that iPhone and the email address associated with your Apple Account. Uncheck any others.

On any Macs you use:

• Change your login password (System Settings > Touch ID & Password)
• Check that nobody in your household has added a fingerprint (System Settings > Touch ID & Password)

Your Apple Account:

• Login to your Apple Account (https://account.apple.com/sign-in)
• Review the "Email & Phone Numbers" section. Remove any that are not yours or that anyone else has access to.
• Review the "Account Security" section and settings. Make sure that the trusted phone numbers and trusted devices listed are all devices that you and only you have complete control of.
• Change your Apple Account password (use a strong password that you do not use anywhere else and that nobody else knows (enter the new password in your password manager)

Email Accounts:

• Change your password for all other email accounts that you use (particularly the ones that you have listed in your Apple Account under "Email & Phone Numbers" and "Account Security".
• Login to each of your email accounts (e.g. Microsoft, Google) and visit the settings. Review all of the security settings, account contact information, two-factor authentication methods, and account recovery settings.
• Review the devices listed as having access or being logged into your account. remove those that are not yours.
• Follow these steps for every email account that you use.

Specifically for the message you posted, this is common when using Safety Check and one of those apps listed has probably been deleted. The Home app is the usual one that people delete and Safety Check is unable to perform that step to stop sharing from those listed apps. Just do what is suggested and remove sharing on each app individually. Don't be concerned about that message, it does not mean anything nefarious is going on and is quite common.

FishingAddict has you covered well with securing your account. The screenshots are helpful to visualize what you are seeing.

The advice you’ve been given is great and I hope it solved any/all issues you reported you (as well as as your family) are having with your devices. What a nightmare!

If you’re still having trouble, I want to let you (and anyone else who stumbles on this thread after googling to find help with compromised devices) You are NOT alone. I know it feels like NO ONE believes you, people think you’re out of your mind, (or that the things you describe aren’t even possible. ) Then there are the ones who KNOW they are…

This kind of activity is actually occurring at an alarming frequency- and it is often spread across every platform in the user’s ecosystem, network wide. It’s a malignant persistence that follows the users from device to device, carrier to carrier, account to account.

I won’t get in to the methodologies at this juncture- I just wanted to type some words into the interwebs to give assurance to here are people out here going through it too. Don’t give up.