How do I secure my iPhone if it is compromised?

As was asked above, what happened? Did somebody get access to your Apple Account, passcode, or physical access to iPhone?

For Apple Account credentials compromises:

• If you think your Apple Account has been compromised - Apple Support
• Safety Check for an iPhone with iOS 16 or later - Apple Support

Knowing an IMEI and device info is not typically a risk with iPhone itself, though it can potentially be a risk for somebody using your info to convince the carrier to alter your phone plan; social engineering.)

There’s no need for a new phone.

Lockdown may or may not be warranted, depending on what happened.

El-Guapo-2 wrote:

Imediately go to settings, scroll down to Privacy & Security, then scroll all the way down to lock down mode. Go through the screens to turn on the feature. Change your passwords. Try calling apple to see if they can do anything about the IMEI. You might have to get a new phone.

Apple can't do anything about the IMEI and suggesting they may need to get a new phone is beyond extreme.

Lovemygems wrote:

The person has all my credentials. Including imei and device info.

[Re-Titled by Moderator]

Original Title: Info breach

Slow down and provide more details on why you think someone has your IMEI and device information. Hacking an iPhone is beyond expensive and only those who are at the highest levels of the world, like elected officials, CEO's of multi-billion dollar companies are worth the expense and even then it's almost impossible.

And the advice above to call Apple to see if they can do anything about your IMEI is beyond bizarre advice.

Imediately go to settings, scroll down to Privacy & Security, then scroll all the way down to lock down mode. Go through the screens to turn on the feature. Change your passwords. Try calling apple to see if they can do anything about the IMEI. You might have to get a new phone.