According to security researcher Lukasz Olejnik, light sensors installed on many smartphones and laptops can be used to steal data. With the help of sensors, devices can automatically adjust the brightness of the screen depending on ambient light, however Oleynik considers them a threat to the security of data.

The World Wide Web Consortium, which develops and implements standards for the Internet, is considering the possibility of providing web sites with access to ambient light sensors without user permission. According to Oleinik, if the web pages have such access, the sensors can be used to detect changes in screen brightness. So they will be able to "read" QR codes. Because QR codes are sometimes used to authenticate a user, for example, when changing a password, the ability of sensors to read them causes an alarm.

Many sites change the color of links when a user visits them. With the help of light sensors, Oleinik managed to fix these changes and thereby track the search history in the browser. A significant disadvantage of the attack - it takes a long time to implement it. The definition of a line of 16 characters took the researcher 48 seconds, and the scan of the QR code - 3 minutes and 22 seconds. Few users will keep the QR code page open for so long.