Mobile phones are everywhere, they have become the main means of communication, but now we use these devices not only to make phone calls, but also to access the Internet, send messages and photos.
Unfortunately, mobile phones were never designed to provide the privacy and security of their owners. They fail to protect your communications from third parties and expose you to more and more types of surveillance, such as location tracking.
As a rule, mobile devices give the user much less control than the same laptop or PC: you cannot change the operating system; it is more difficult for you to understand how the attack was carried out using malware; difficult to remove or replace unwanted software that was preinstalled. What’s more, your mobile operator can monitor you and how you use your phone. The device manufacturer is also able to claim that your device is out of date and stop providing you with software updates, including new system security updates. If this happens, you will be left unprotected in a world where there is a lot of malware.
We invite you to read our translation of an article by the Electronic Frontier Foundation on how a smartphone can become a surveillance tool and jeopardize the privacy of its owner.
Location Tracking
The biggest but almost invisible threat to your privacy that mobile phones carry is that they report your location around the clock. There are at least four ways in which a phone’s location can be tracked.
1 cell towers
In all mobile networks, the operator can figure out where a particular subscriber’s phone is when the device is turned on and connected to the network. The ability to do this depends on how the mobile network is built. This technique is commonly referred to as triangulation.
An operator can track the device’s location by analyzing the signal strength that different towers receive from a particular subscriber’s mobile phone, and then calculate where that phone should be located. The accuracy with which an operator can determine a subscriber’s location varies depending on many factors, including the technology used by the operator and the number of cell towers in an area. You can track down the phone of a particular subscriber up to the block, and sometimes even at home.
There is no reliable way to hide from this kind of surveillance while your mobile phone is on and transmitting signals on the operator’s network. While usually only the mobile operator itself can perform this kind of tracking, it is also within the power of the government to force it to transmit a particular user’s location (real-time or ex-post).
In 2010, a German privacy advocate named Malte Spitz used a privacy law to force his mobile operator to hand over records related to his location. He decided to publish them as a cautionary tale so that other people understand how mobile operators are able to control their users in this way. The possibility of government access to this kind of data is not something fictional: this approach has long been used by law enforcement agencies in countries such as the United States and Russia.
Another type of tracking related to this is as follows: the government asks the mobile operator for a list of all mobile devices that were "spotted" in a certain area at a certain time. This data can be used to investigate a crime or to find out who was present at a particular protest. For example, the Ukrainian government used this method in 2014 to get a list of all the people whose mobile phones were present at an anti-government rally.
Phone owners also share their location data with each other. This information is less accurate than tracking data that is obtained from multiple towers, but it can still be used to obtain the location of a specific device. This is often abused by commercial services that request such data in order to determine where a certain phone is currently located. Unlike previous tracking methods, this method does not require operators to be forced to transfer their users’ data. Instead, this approach uses location information that was available to commercial organizations.
2 Fake towers and IMSI "catchers"
A government or other tech-savvy organization may be collecting your location data directly, such as using the Cell Site Simulator (a portable fake cell tower that looks like the real thing). It is able to detect mobile phones of specific users and track their location. It is also worth mentioning here IMSI, the International Mobile Subscriber Identity, which will also be obtained by a special "catcher", and is able to identify the SIM card of a particular person.
Such an IMSI "catcher" must be installed in a specific location in order to find and track nearby devices. Currently, there is no reliable protection against IMSI “catchers". Some apps claim to be able to detect them, but this feature hasn’t been perfected yet. To protect yourself, it’s a good idea to disable 2G connectivity (the device will only connect to 3G and 4G networks) and roaming calls unless you plan to travel to countries where your carrier is not available. These measures will help protect yourself from being tracked by IMSI catchers.
3 Wi-Fi and Bluetooth tracking
Modern smartphones have other signal transmitters in addition to the mobile network, such as Wi-Fi and Bluetooth. These signals are transmitted at a lower power than calls and can usually only be tracked within a short range (eg, within the same room or building), although sometimes using a sophisticated antenna can detect them from longer distances.
In an experiment in 2007, a security expert in Venezuela was able to trace a Wi-Fi signal over a distance of 382 km in a rural area with little radio interference. Both Wi-Fi and Bluetooth have a unique device serial number called a MAC address, which can be tracked by anyone who receives a signal. The device manufacturer sets this address at the time the device is created, and it cannot be changed by software.
Unfortunately, the MAC address can be tracked through Wi-Fi signals even if the device is not connected to a specific wireless network or is not transmitting data. Whenever Wi-Fi is enabled on a smartphone, it will transmit random signals that contain the MAC address and thus allow third parties nearby to discover that particular device. This approach has been used for commercial tracking applications, for example, to allow store owners to get statistics on how often specific customers visit their store and how long they spend there. Since 2014, smartphone manufacturers have begun to acknowledge that this type of tracking does have its drawbacks, but the problem remains relevant today.
Compared to GSM monitoring, this form of tracking is not very useful to the government. This conclusion can be drawn because tracking is only possible over a short distance and requires preliminary data or observation of the user in order to determine his MAC address. However, this form of tracking is a very accurate way to determine when a person is in or out of a building. Disabling Wi-Fi and Bluetooth on your smartphone can prevent such snooping.
Wi-Fi network operators can also view the MAC address of every device that is connected to their network. This means that they are able to recognize certain mobile phones even over time, identifying them as having been connected before.
On some devices, it is possible to physically change the MAC address in such a way that other people cannot recognize it over time. On them, using the right software and settings, it would be possible to set a new MAC address at least every day. This usually requires, as already mentioned, special software, such as an application to change the MAC address. However, this option is currently not available for most smartphone models.
4 Leakage of location information from the Internet and applications
Modern smartphones give you the ability to determine your location using GPS, and sometimes other services provided by geolocation companies. Applications can query your phone for location information and use it to provide certain services based on the information it receives.
Some of these apps (like maps) share your location with your service provider, who in turn makes it possible for other people to track you. App developers may not have wanted to track user movements in the first place, but they can do it anyway.
Smartphones give you some control by allowing or denying apps from accessing your location. It’s a good practice to protect your privacy by trying to limit which apps can access this information. At a minimum, you should make sure that your location is only available to apps that you trust and have a good reason for accessing this kind of data.
Location tracking is not just about finding out where a person is right now. It can also be a request to get the history of movements for a selected period of time. For example, location tracking is used to find out if certain people are in a romantic relationship; to understand who attended an important meeting or who attended a protest against the government.
In December 2013, the Washington Post reported on the NSA’s location-tracking tools, which collect vast amounts of information "about the location of mobile phones around the world." It does this mainly by tracking phone company towers. A tool called CO-TRAVELER uses the data to look for relationships between the movements of different people to find out who, for example, travels together.
How to avoid being tracked
Turn off your phone
It is widely believed that phones are used to monitor people, even if they are not actively using them to make calls. As a result, if you are having a private conversation, it is advisable to completely turn off your phones (or even remove the batteries from them).
The recommendation to take out the battery seems to be mainly due to the existence of malware that causes the phone to turn off at the request of a scammer (showing only a blank screen), while in fact it remains on and is able to monitor your conversations. Thus, people will be fooled into thinking that they have definitely turned off their phones, when in fact they have not. Such malware does exist, so be careful.
Turning off the phone has one potential downside: if many people in the same place do it at the same time, it will be a definite sign for mobile operators, as they will assume that something has happened. That "something" could, of course, be the beginning of a movie at the cinema or the departure of a plane from the airport, but (at the same time) also a private meeting or conversation. An alternative to this step is a simple solution: leave your phones in another room so that scammers cannot eavesdrop on you even through the microphones of the devices.
Disposable phones
Phones that are used temporarily and then thrown away are called disposable phones. People who are trying to avoid government surveillance tend to change mobile phones (and numbers) frequently to make it harder to trace their conversations. They use phones unrelated to their identities to make sure they are operating undercover.
This type of phone has a number of limitations.
First, simply replacing a SIM card or changing a phone does not provide a person with complete protection of their data, since mobile operators monitor both the SIM card and the device itself. In other words, the network operator knows which SIM cards were used in which devices and can track them either individually or together.
Second, the government is developing methods for analyzing the location of mobile devices, by which movement tracking can be used to make guesses or hypotheses about whether multiple devices really belong to the same person. There are many ways to prove it. For example, a security analyst might check whether two devices tend to move together or, even if they are used at different times, to be in the same place.
Another problem with using anonymous phone services is that people’s calling patterns tend to be similar. For example, you usually call your family members and work colleagues. Even though each of these people receives calls from a wide range of people, you are probably the only person in the world who routinely calls both of them from the same number. Thus, even if you suddenly change your number and then resume the same patterns in calls, it will be easy enough to determine which number was previously yours.
There is a special Hemisphere database (where call histories are stored), using it, governments and authorities can track disposable phones by following the similarity of their call patterns. Disposable phones are considered disposable because a person uses them only once, but the algorithms of this database analysis will help to establish a connection between one phone and another. This will be easily done if both phones were used to make or receive calls from the same numbers.
All these facts mean that the effective use of disposable phones to hide one’s identity from government surveillance includes the following:
- Do not reuse either the SIM card or the device.
- Do not wear different disposable phones together.
- Use phones in different places.
- Do not make or receive calls from the same people using different devices.
This is by no means a complete list: for example, we did not consider the risk of observing the place where a disposable phone was sold or the places where it is used; or the ability to install specific person voice recognition software as an automated method of determining who is speaking on a particular phone.
A bit about GPS
GPS allows devices anywhere in the world to quickly and accurately determine their location. The function works based on the analysis of signals from satellites. There is a common misconception that these satellites somehow track users or know where they are. In fact, GPS satellites only transmit signals, they do not record or store any data. Moreover, operators of satellites and GPS systems do not know where a particular user or device is located.
This can be considered true, since individual GPS receivers (such as those inside smartphones) calculate their own positions by determining how long it took radio signals from multiple satellites to reach the device.
But why are we still talking about GPS tracking, then usually this tracking is done by applications running on a smartphone. They ask the phone’s operating system for its location (which is determined using GPS). The apps then pass this information on to someone else using an internet connection.
There are also tiny "GPS bugs" that can be secretly hidden in someone’s belongings or attached to a vehicle. These bugs determine their own location and then actively relay it over the network to another person.
"Earvesting" of mobile communications
Cellular networks were not originally designed to use technical means to protect subscribers’ calls from eavesdropping. In other words, a person with the right radio receiving equipment was able to listen to calls.
Today the situation has changed for the better, but not much. Encryption technologies have been added to mobile communications standards to prevent eavesdropping. But many of these technologies were poorly developed (sometimes deliberately, due to government pressure). They have been unevenly deployed, so they may be available in one medium but not in another, in one country but not in another. For example, in some countries carriers do not include encryption at all or use outdated security standards. This means that someone with the right device can intercept other people’s calls and text messages.
Even when the best industry standards and technologies are used, there are still people who can eavesdrop on your conversations. At a minimum, mobile operators themselves have the ability to intercept and record data about who called or wrote to whom, when and what they said. This information may also be available to the government. In addition, IMSI catchers (which we talked about earlier) are able to track your location.
Many people believe that traditional calls and SMS messages are not protected from eavesdropping or recording. Although the technical details vary considerably from place to place and system to system, the technical protections are indeed very weak and unreliable.
The situation changes when you use secure messengers for communication, because they can use encryption to protect your correspondence and calls. This encryption provides more meaningful protection. The level of protection you get from using secure communications applications to communicate depends largely on which applications you use and how they work. An important question is also whether this application uses end-to -end encryption to protect your communications and whether the developer has any way to cancel or bypass this encryption.
Phone is infected with malware
The phone can get a virus and other types of malware for many reasons: the user was deceived when installing software; someone was able to hack into his device; there are security defects in existing software. As with other types of computing devices, malware can spy on the user. For example, it may view and share your personal data (such as saved text messages or photos). The program is also capable of activating certain device sensors such as microphone, camera, GPS to follow you.
This method is used by some states to spy on their people using their own phones. People react to this fact quite soberly, leaving their mobile phones in another room during a private conversation or turning them off.
Another problem is that malware could theoretically make the phone "pretend" to be off while it remains on (even with a black screen, the phone will work). In this case, it is better to play it safe and remove the battery from your device during confidential negotiations.
Examination of the seized phone
Forensic analysis of mobile devices is a fairly developed area in the world. An expert analyst connects the seized device to a special machine that reads the data stored inside it, including records of actions taken, phone calls made and text messages sent. Forensic analysis will help restore access to deleted text messages. With it, you can sometimes bypass the screen lock, especially for older phones.
There are many smartphone apps that try to disable or prevent forensic analysis of data and records, or encrypt existing data to make it unreadable to the analyst. In addition, there is a special Remote Wipe software that allows the owner of the phone to wipe certain data remotely at his request.
This software will be useful for protecting your data from criminals. Note, however, that intentionally destroying evidence or obstructing an investigation can be treated by a court as a separate offense, often with very serious consequences.
Analysis of phone usage patterns
The government is also using computers to analyze data on many users’ phones to automatically find certain patterns or usage patterns. These models allow the security analyst to find instances where people have used their phones in unusual ways, such as taking special precautions regarding their privacy.
Here’s what the government can find out by doing data analysis: do people know each other; when one person uses several phones or changes many devices in a short period of time; when people travel together or meet each other regularly; when people use their phones in a suspicious way.
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According to EFF.