A study conducted in Germany, at the Institute of Information Security and Dependability of KIT Karlsruhe reveals a new privacy issue that is far from theoretical: even a common home WiFi network can be used to track the profiles of people within its range, even recognizing them, tracing a sort of radio profile. The peculiarity is that it is not necessary for the subjects to carry connected devices such as smartphones, tablets, or smartwatches which, as is known, by connecting to network devices reveal our location at all times.
WIFI KNOWS WHO WE ARE
The German research sheds new light on WiFi, especially considering that it is now everywhere: in our homes, in all offices, in restaurants, hospitals, public offices, airports, and even in open urban spaces, as a service provided by municipal administrations.
THE RESEARCH
The title chosen by KIT, the acronym for Karlsruhe Institute of Technology (one of the most advanced in Europe), to publicize the study results is emphatic, but supported by evidence: “The Spy Who Came in from the WiFi: Beware of Radio Network Surveillance!”. By exploiting the so-called beamforming feedback information, also known as BFI, that is, feedback information that devices regularly send to the router to help it better direct the WiFi signal, it is possible to also map how a person alters radio signals. A sort of sonar, in short, with waves that, bouncing here and there, draw what is around the devices.
PROFILING AND COMPARISON
With machine learning, when the waves “construct” the silhouette of an individual, assigning them a unique profile, it is possible to compare it with those already learned to recognize a person already known to the system or to register a new one. In the study, conducted on 197 participants, the system managed to recognize people with an accuracy close to 100%, regardless of the observation perspective and their gait. The result goes beyond simple presence or movement detection: the radio profile is associated with a specific person.
DID SPIES AND HACKERS KNOW EVERYTHING?
An issue that the Institute of Information Security and Dependability of Karlsruhe has documented only now but that could already be known to malicious actors and intelligence agencies. For this reason, one of the researchers, Julian Todt, warns that this technology turns every router into a potential surveillance tool. Felix Morsbach, for his part, admits that nowadays those who commit cyber abuses aimed at control “bypass” the defenses of video surveillance systems (cameras and digital intercoms) but acknowledges that with WiFi there is access to a more pervasive tool.
