iOS 27 Adds Impersonation Risk Detection as Some iPhone 18 Pro Users Report Face ID Crashes

Impersonation Risk Detection is designed to catch users during scams that biometric authentication and two-factor authentication are poorly suited to stop. A common example cited by 9to5Mac is a threat actor posing as a bank's fraud department and walking a user through moving money into a 'safe account' or resetting a password. When a user sends a payment or changes an account password inside a supported app, the app can request a risk read from the iPhone. Apple says the system considers previous interaction patterns, timing, context, and even basic sensor data to decide whether the action is legitimate.

According to Apple, the feature does not examine content in Photos, Messages, or Mail for context, and it does not look at the point of intrusion. The app receives only one word: Unknown, Medium, or High. Unknown means nothing was tripped, which Apple notes is not a confirmation that the user is safe. If the result is Medium or High, iOS does not freeze the money transfer, block the password change, or display a system alert. Apple provides the risk level to the app and leaves the developer to decide what happens next, such as asking the user to verify their identity again or adding a delay before critical settings can be changed. Apple also says it does not control how an app uses the flag, so different apps may treat the same risk level differently.

Users can review the feature's activity in Settings. The recent activity section shows which apps have requested a risk assessment and what action triggered it, and users can revoke access for each app. 9to5Mac criticized Apple for shipping the feature off by default, about four taps deep in Privacy and Security in iOS 27 Settings, behind a toggle labeled 'Share with App Developers.' The report argued that people who find the toggle likely do not need the feature, while those who need it may never look for it, and said it should be enabled by default. Apple did implement a 24-hour delay before the feature turns off, similar to the security delay in Stolen Device Protection, so a threat actor walking a victim through disabling it during a phone call would have to wait at least a day. The setting can be turned on under Settings > Privacy & Security > Impersonation Risk Detection > Share with App Developers.

The Face ID issue affects the iPhone 18 Pro and Pro Max, which introduced a smaller Face ID system with the infrared camera hidden behind the screen near where the time appears in the status bar, according to 9to5Mac. Multiple iPhone 18 Pro owners have reported that their device freezes and reboots after a failed Face ID attempt. 9to5Mac said it reproduced the bug on at least one European iPhone 18 Pro model, while the scope is unclear and it does not appear to affect everyone.

The problem appears when Face ID is used to unlock a protected app, such as the Passwords app, private tabs in Safari, or other apps a user has locked behind biometric protection. It does not seem to be triggered directly from the lock screen. To reproduce it, 9to5Mac said, a user can cover their face with a hand during a Face ID challenge to simulate a first-attempt failure, then tap 'Try Face ID Again' in the alert. If the bug occurs, the phone locks up and stops responding to touch input before rebooting to the lock screen after a few seconds.

In a Reddit thread of complaining users, one person said they contacted Apple support and were apparently recommended a hardware swap. 9to5Mac said this is probably a misdiagnosis and that the problem will likely be fixable with a software update. The report also noted a similar iOS 27 bug that can trigger system reboots on any iPhone model, which it expects to be fixed by a forthcoming software patch. 9to5Mac said it had reached out to Apple for comment.

Editor's Summary

Apple's iOS 27 introduces Impersonation Risk Detection, an opt-in anti-scam tool that gives supported apps a risk rating during payments or password changes, but it is disabled by default and leaves enforcement to app developers. Separately, some iPhone 18 Pro users report failed Face ID attempts causing freezes and reboots, a problem 9to5Mac says is likely software-related and may be addressed in a future update.