Samsung Galaxy S10 Fingerprint scanner accepts every finger

Samsung Galaxy S10 Fingerprint Scanner

A troublesome issue has come to light with the ultrasonic fingerprint scanner of the new Samsung Galaxy S10. By using a specific screen protector, the device can be unlocked by unauthorized individuals. Samsung says it will soon come up with an update that will close this privacy breach.

Ultrasonic scanner

The Samsung ultrasonic scanner is supposed to be a new and secure method to lock your phone with a fingerprint. Now it appears that this method might not be secure as it’s supposed to be. The scanner works with sound waves that record the reflection pattern of the fingerprint when set. However, certain silicone screen protectors can apparently disrupt this process. Using cheap screen protectors from Ebay can render the fingerprint security features useless.

Accidental discovery

The error was discovered by a British couple. After setting her right thumbprint, the woman realized that she could also unlock the phone with her left thumb. Then it turned out that her husband could also open the phone without a problem. When she subsequently tried out the case on the S10 of an acquaintance, the same thing happened. The screen protector was indeed the culprit.

Samsung acknowledges the problem and says it’s working on a software patch that should solve it. A logical solution would be to report when such a case cannot find a fingerprint. In this way, the consumer could be notified when they have purchased a wrong cover. However, until that time it might be wise to go back to a PIN code to lock your Galaxy S10.

Possible infringement

A video on Twitter shows how a device is unlocked with the silicone sleeve after the fingerprint has been set without the case. This would mean that someone with such a case could always enter your S10 when you’ve locked it with a fingerprint.

Cybersecurity analyst
David is a cyber security analyst and one of the founders of Interested in the "digital identity" phenomenon, with special attention to the right to privacy and protection of personal data.