The Google Pixel 4 was officially announced last week and while it won’t be shipping until October 24th, review units have already started going out. Gone is the fingerprint scanner which has been replaced with the Pixel 4 Face Unlock feature instead. While it is quick and works great on our Pixel 4 XL review unit, it has raised some security concerns due to the fact it will work with your eyes closed.
UPDATED (10/21/2019): Google has addressed the issue in a statement to The Verge:
We’ve been working on an option for users to require their eyes to be open to unlock the phone, which will be delivered in a software update in the coming months. In the meantime, if any Pixel 4 users are concerned that someone may take their phone and try to unlock it while their eyes are closed, they can activate a security feature that requires a pin, pattern or password for the next unlock. Pixel 4 face unlock meets the security requirements as a strong biometric, and can be used for payments and app authentication, including banking apps. It is resilient against invalid unlock attempts via other means, like with masks.The Verge
So a fix is incoming, the only question is how much later rather than sooner it will be rolled out. On that note, if you’re really concerned about keeping your new Pixel 4 or 4 XL locked down, you may want to stick to a PIN unlock until it does.
First discovered by the BBC and confirmed by Google, we can also confirm that this is indeed the case.
I’ve personally used a number of devices with Face Unlock features and in most cases they work equally well with my glasses on or off. Sometimes you need to do a couple of face scans, one with and one without. When setting up the Pixel 4 Face Unlock feature, I was at first impressed with the lengths Google is going to scan your face. Not content with just a frontal image, the feature requires you to tilt your head up and down, as well as left and right, to get a full scan. This is required as Google touts the speed of the feature which starts to scan for and unlock your face the moment you pick up your device.
And work quickly it does. In more than a few cases, my phone has been unlocked by the time I’m ready to start using it at the optimal viewing angle. Worst case scenario, I have to wait a second or so before it is unlocked and ready to go. The feature works equally well with my glasses on or off, as mentioned above. However, it also works when my eyes are closed, potentially allowing someone to unlock and access your device while you are sleeping.
I currently have a Galaxy Note10+ for review (review coming soon on that one) and I can confirm that while that Face Unlock works with my glasses on or off, when my eyes are closed the screen displays a “No face detected” message.
As mentioned above, this was first reported by the BBC and then confirmed in a Google support post.
Your phone can also be unlocked by someone else if it’s held up to your face, even if your eyes are closed. Keep your phone in a safe place, like your front pocket or handbag.Google support post
Google’s solution for this is to enable the lockdown option which will add a new option which disables notifications, Smart Lock, fingerprints, and Face Unlock while your screen is off.
You can turn off notifications, fingerprint or face recognition unlocking, and Smart Lock while on your lock screen with lockdown.
Show the lockdown option in your power settings
• Open your phone’s Settings app.
• Tap Display And then Advance And then Lock screen display.
• Turn on Show lockdown option. The lockdown button will show in the list of settings when you press the power button.
Turn on lockdown
• Lockdown will only work until you unlock your phone. If you want keep using lockdown, turn it on each time you want to use it.Google support post
• Hold the power button for a couple seconds.
• Tap Lockdown.
Most devices with Face Unlock also have a fingerprint option as well. Unfortunately, Google has gone all in with Face Unlock so if you want to use biometrics with the Pixel 4/4 XL, you’ll have to accept the possibility your phone can be unlocked while your eyes are closed or you are sleeping. Personally, I would have like to see Google keep the fingerprint scanner and give users a choice as to what biometric option they want to us. If you are concerned about this potential security hole, you can always disable Face Unlock and just use a pin to unlock your phone.
Unfortunately, we can’t post images or video of the Face Unlock feature due to embargo but once that embargo lifts on Monday we’ll add a few screenshots and images.