With iOS 11, you can still bypass the iPhone lock screen and trick Siri into getting into a person's phone. The bypass is the same as it was in the earlier version of the operating system:
- Press the home button using a finger not associated with your fingerprint authentication, prompting Siri to wake up.
- Say to Siri: Cellular data.
Siri then opens the cellular data settings where you can turn off cellular data.
As was the case before, anyone can do this. It doesn't have to be the person who "trained" Siri.
By also turning off Wi-Fi, you cut off her connectivity access. You will get an error saying, “Siri not available. You are not connected to the internet.” But you don’t care about that error because you have already bypassed the iPhone lock screen.
Other privacy holes remain
Also still an issue: Anyone can use Siri to read your new/unread text messages, send text messages and see your most recent phone call.
To do that, again prompt Siri to wake up using a finger not associated with the phone's authentication. Then say, “Read messages,” and Siri will read any unread text messages from the lock screen. Say, "Send a text message [person's name]," and Siri will let you dictate a message and send it. Say, "Show me recent calls," and Siri will display your most recent phone call.
Facebook privacy hole closed
Apple has closed the hole that allowed you to command Siri to post to Facebook. Now, she tells you she can't do it and gives you a button to open Facebook. You need to enter the passcode for the device to open the app.
Lock down your privacy
Until Apple patches the hole that lets you bypass the lock screen and let you command Siri, your best option is to disable Siri from the lock screen