A smartphone makes use of more power when it is further away from a cellular base and way more barriers are in its way as it reaches for a signal.
An application is created, which is designed to collect data about power consumption.
“The malicious app has neither permission to access the GPS nor other location providers (e.g. cellular or Wi-Fi network),” said the team of Dan Boneh, Yan Michalevsky and Aaron Schulman, from the computer science department at Stanford University, together with Gabi Nakibly, from Rafael Ltd – wrote in their paper.
“We only assume permission for network connectivity and access to the power data.
“These are very common permissions for an application, and are unlikely to raise suspicion on the part of the victim.”
According to reports there around 179 applications available on Android app store on the Google Play that will ask for this information, the team added.
Activities such as listening to music, taking voice calls, activating maps or using social media etc. drain the battery however this can be reduced due to “machine learning”, according to the reports..
“Intuitively the reason why all this noise does not mislead our algorithms is that the noise is not correlated with the phone’s location,” it says.
“Therefore a sufficiently long power measurement (several minutes) enables the learning algorithm to ‘see’ through the noise.”
The test had been done on the smartphones using the 3G networks but did not calculated signal strength as that data is secured by the device.
Abundance of sensors
“With mobile devices now becoming ubiquitous, it is troubling that we are seeing so many ways in which they can be used to track us,” stated Prof Alan Woodward, the cyber-security expert from Surrey University.
“I think people sometimes forget that smartphones are stuffed full of sensors from gyroscopes and GPS to the more obvious microphones and cameras.
“This latest work shows that even that basic characteristics (power consumption) has the potential to invade privacy if monitored in the right way,” he added.
“We are approaching the point where the only safe way to use your phone is to pull the battery out – and not all phones let you do that.”