In modern smartphones, screen fingerprint scanners are becoming more and more popular. Most people think that this authentication method is the most convenient, if not the fastest. However, the technology of combining the screen with a fingerprint scanner has a drawback, which until recently was not known.
The Xiaomi Sub-Screen Fingerprint Scanner can be used as a camera
It was discovered by one of the enthusiasts who shared his discovery on the Reddit forum. He claims that in the hidden settings of the Xiaomi Mi 9T, he discovered the ability to see what the micro-camera of the optical fingerprint scanner records. Supporting his words, he posted a video showing this “feature” on the forum. You can watch the video below.
A Redditor has found a hidden activity on a Xiaomi phone that lets you see the first power supply from the Goodix Optical Fingerprint Scanner.https://t.co/RKpjDTdgzG
OEMs should not really leave these debugging applications on production versions… pic.twitter.com/fnEpvPZtol
– Mishaal Rahman (@MishaalRahman) August 10, 2020
The image quality and resolution are not perfect at all, so you will not be able to see anything. However, despite this, the XDA-Developers portal member, Mishaal Rahman, believes that this is a dangerous vulnerability that must be ruled out. He argues that this defect has nothing to do with the safety of the sensor itself. The problem is the firmware itself.
At the moment, Xiaomi has not reacted in any way to the discovery and there is no information whether it will correct the defect in its devices that have fingerprint scanners.
It is worth noting that Xiaomi uses on-screen fingerprint scanners on various mid-range and high-end devices, including the popular Mi 9T, the hero of this discovery. The smartphone was released last summer and here is a reminder of its specifications.
Xiaomi Mi 9T Specifications
- 6.39 inches (2340 × 1080 pixels) Full HD + 19.5: 9 aspect ratio AMOLED HDR screen with 103.8% NTSC Color Gamut, 600nit (HBM) / 430nit (Typ), Corning Gorilla Glass 5 protection
- Octa Core (2.2GHz Dual + 1.8GHz Hexa) Snapdragon 730 Mobile Platform with Adreno 618 GPU
- 6 GB LPDDR4X RAM with 64 GB / 128 GB storage (UFS 2.1)
- Android 9.0 (Pie) with MIUI 10
- Dual SIM (nano + nano)
- Rear camera 48MP with dual LED flash, aperture f / 1.75, sensor 1/2 IM Sony IMX582, size 0.8μm pixel, 6P lens, telephoto lens 8MP 1/4 with with a size of 1.12μm pixel, aperture f / 2, 4 for 2x loss – smaller zoom, 13MP 1/3 ″ 124.8 ° ultra wide sensor, size 1.12μm pixels, aperture f / 2.4
- 20MP front camera with f / 2.2 aperture, pixel size 0.8μm
- On-screen fingerprint sensor
- 3.5 mm audio jack, Qualcomm WCD9375 Hi-Fi audio chip
- Dimensions: 156.7x 74.3 × 8.8; Weight: 191g
- Dual 4G VoLTE, WiFi 802.11 ac (2.4GHz + 5GHz), Bluetooth 5, GPS + GLONASS, NFC, USB Type-C
- 4000mAh (Standard) / 3900mAh (Minimum) battery with fast charging 18W