Independent security researcher Lukasz Olejnik claims Ambient Light Sensors in personal devices could be used to track users and even measure the size of their homes.

The sensors allow devices to detect the brightness of their environment but the technology may introduce non obvious and unexpected data leaks such as information about the size of a user's house,  what times the user is usually working, what light conditions they prefer, and how often they move between rooms, according to an Aug 31 blog post.

Using this information advertisers, or attackers, could potentially profile users and make assumptions about a user's financial situation to serve targeted ads based on assumption such as large house equals wealthy user.

The sensor could also be used for cross device aspects including linking and tracking, the post said. To better protect users, Olejnik said the readout of the sensors should be protected.