5 Non-obvious Ways To Spy On You With A Smartphone

To reveal your location, you do not even need GPS, and you can pull off the password and even with a gyroscope.
Last Updated
June 12, 2020

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You surely know that your smartphone may well be used against you. By hacking the gadget, you can access its cameras or microphones. So everything you shoot and say can be passed on to third parties. The possibilities of modern smartphone espionage are not limited to this. In theory, there are a number of other less obvious ways to get information about where you are and what you are doing now.

All modern smartphones are equipped with a gyroscope. This sensor is needed to determine the exact direction of the tilt of the gadget, which can be used to automatically activate some functions or control the car in the racing game.

Every year these sensors become more accurate. Theoretically, their sensitivity to the slightest fluctuations can be used by attackers against you. It's proven.

When you use a screen keyboard, your smartphone bends slightly with every touch. By recognizing the slightest bias with a gyroscope, the keylogger can guess the approximate text you type. Possible options are adjusted to take into account the intensity of the sound emanating when the display glass is taped. Smartphone microphones are already helping with this. Using a combination of these sensors and a set of algorithms, the researchers were able to guess the pressed keys with 90-94% accuracy the first time.



Location without GPS

Even if the GPS is turned off, you can determine the location of the device by using cell towers and Wi-Fi points with geolocation information tied to them. However, you can even get information about the user's location without accessing such data.

The same group of researchers from Northeastern University tried

Taking as a basis a map of the area in which the person was located, the application allowed to track all movements on the car. The accelerometer was used to detect movement and stops. The magnetometer recorded the direction of movement. The gyroscope measured the angles of the turn, allowing accurately tracking when and in which direction the machine was turning.


A special algorithm combined data from all these sensors and formed an approximate pattern of movement. It was compared with the real routes in the area where the surveillance was carried out. According to such data, it is possible to determine exactly where and when the user went, how much time he spent on it.



Tracking through advertising banners

There is another way to determine a person's location without direct access to the GPS data of his smartphone. This method was described by researchers at the University of Washington who used banner advertising for mobile. The minimum deposit for placing such an ad through Google AdWords and Facebook was $1,000.

When you buy such a banner, you can specify in which application and for which unique device identifiers you need to display. The researchers also pointed to a three-mile square geozone that featured ads in selected applications.

Each time the target phone used a given app, information about the device, time and location was sent to the holders of the banner. Using this information, the research team was able to track the user's location within 25 feet (7.6 meters). However, this is possible as long as the application stays open for four minutes or has been launched twice in the same location.

Of course, this method of surveillance requires constant use of a certain application. This is partly an obstacle that can be circumvented by placing banners in the most popular programs. You also need to know in advance the specific advertising ID of a particular person's device. However, even without it, this method can be used to monitor the population of the chosen location.



The ambient light sensor allows you to adjust the brightness of your smartphone's display. You will be surprised, but even this seemingly harmless sensor can be used against you.

Lukasz Olejnik illustrated this

Websites can display different colors for links. For example, the text may be light blue if you haven't visited it before, but it will turn purple after the first click. The site itself, of course, can not recognize what color the link is displayed for a particular user, because the transitions fix the browser. However, if web resource representatives have access to your smartphone's light sensor data, they can determine if you've moved on to the link you've been using before or not.

This is especially evident in contrasting pages with a dark text background and light selection of hyperlinks. Once you stumble upon them, the sensor recognizes the increase in the level of light from the screen. In theory, you can create lists of all the pages you visit without your knowledge.



Identification of users and objects nearby

The vast majority of smartphones have an approximation sensor. It is used to disable the touch screen when you call. Otherwise, during the conversation, you would face to continue to press the buttons on the display.

This sensor not only detects that objects are close to the screen, but can also measure the distance to them. Each of us keeps the smartphone at a different distance depending on height, arm length, vision and other factors. Based on all this information, the app may well differentiate users and their behavioral characteristics.

The accuracy of this method may be low, but in combination with the same targeted mobile banners, advertisers can identify their target audience. In addition, the approximation sensor can determine the distance to nearby objects surrounding the user. And this can be an additional tip when spying without the use of GPS.

Each of these methods is still described as theoretical. So far, none of them have been widely distributed. However, it is possible that it is only a matter of time.

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