An unusual method of stealing data from surveillance cameras

We explain in simple terms research that demonstrates a vulnerability in modern digital video cameras.

Scientific research into hardware vulnerabilities often paints glamorous espionage scenarios, and a recent study by researchers at universities in the United States and China is no exception. They found a way to steal data from surveillance cameras by analyzing their stray electromagnetic emissions – aptly named the attack EM.

Reconstructing information from stray emissions

Let’s imagine a scenario: a secret room in a restricted-access hotel is hosting secret negotiations, the identities of the people in the room are also considered sensitive information. There is a surveillance camera installed in the room that runs around the clock, but the recording computer is impossible to hack. However, there is a room next door to the secret room that is accessible to other, regular guests of the hotel. During the meeting, a spy enters the adjacent room with a device that, for simplicity’s sake, we will consider a slightly modified radio receiver. This receiver collects data that can later be processed to reconstruct the video from the surveillance camera in the secret room! And the reconstructed video will look something like this:

Images from radio noise

The authors of the recent study, however, work with much weaker and more complex electromagnetic interference. Compared to encryption devices of the 1940s and computer monitors of the 1980s, data transmission speeds have increased significantly, and although there is now more stray radiation, it is weaker due to smaller components. However, researchers take advantage of the fact that video cameras have become ubiquitous, and their design – more or less standardized. A camera has a light-sensitive sensor — the raw data from which is usually transmitted to the graphics subsystem for further processing. It is this process of raw information transmission that the authors of the study studied.

In some other recent experiments, researchers demonstrated that electromagnetic radiation generated by data transmission from a video camera sensor can be used to determine the presence of a nearby camera—to protect against unauthorized surveillance. Valuable information. But, as it turns out, a lot more information can be gleaned from interference.

Pocket spy

But some of the researchers’ findings seem even more troubling. For example, the exact same interference is generated by the camera in your smartphone. Well, if someone starts following their target with an antenna and radio receiver, they will be noticed. But what if an attacker gives a potential victim a slightly modified power bank? By definition, such a device is likely to be close to a smartphone. When the victim decides to shoot a video or take a photo, the latest “bug” can reliably block the resulting image. The example below shows how serious the damage caused by such interference can be when, for example, photographing documents using a smartphone. Quality is sufficient for reading text.

However, we do not want to overstate the risk of such attacks. This research will not lead to attackers stealing photos tomorrow. But research like this is important: ideally, we should apply the same security measures to hardware vulnerabilities as we do to software. Otherwise, a situation may arise where all the software protection measures for these smartphone cameras will be useless against a hardware “bug” that, although complex, is complete with components available at the nearest electronics store.

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