The Unauthenticated Call
By default, if you hold down the side button on a completely locked iPhone, Siri will activate. Even if the phone is protected by Face ID and a strong passcode, a stranger can instruct Siri to “Call Mom” or “Call 911.” Siri will execute this “Voice Dialing” command without ever asking for a passcode to verify the user’s identity. While designed for emergencies, this is a massive privacy loophole that allows anyone who steals your phone to harass your contacts or rack up international calling charges. You must permanently lock the dialer.
How to Turn Off Voice Dialing
You can permanently hide the outgoing dialer API behind the passcode wall via the Face ID settings.
- Open the Settings app on your iPhone.
- Scroll down and tap on Face ID & Passcode (or Touch ID & Passcode).
- Enter your device’s master PIN code to access the secure menu.
- Scroll down to the section labeled “Voice Dialing.”
- Toggle this specific switch to the Off position (the green background will disappear).
Secured Telephony
The change takes effect instantly. The iPhone will completely sever Siri’s connection to the cellular modem while the device is locked. If someone steals your phone, triggers Siri, and says “Call John,” the operating system will absolutely refuse to place the call. Siri will respond by stating that you must unlock the iPhone first. This guarantees that absolutely no outgoing voice communications can be established without your explicit, biometric authorization.