Bug hunt. Spying devices and how to detect them

One might think that bugs from spy movies got obsolete nowadays. Who needs this stuff if microphones and cameras are everywhere – in laptops, smartphones, and zillions of other devices? However, in most cases, it is more difficult to get access to these gadgets than to the physical space where they are located. Here is where miniature, barely visible, and top-notch equipment comes into play. Let’s try to find out whether ordinary people should be concerned about spying tools potentially used against them and what security precautions should be taken, if any.

Common sense and vigilance

Compulsive thoughts about possible surveillance may quickly drive a person to paranoia. The humanity is rapidly moving towards a ‘transparent’ society; so, somebody is definitely watching you. To retain sanity, one has to focus on the practical approach: what can someone gain from watching me, and what do I have to lose?

Unfortunately, if you run a business, or are famous, or have access to commercial secrets, you are potentially at risk. Take, for instance, high-profile scandals involving hidden cameras in residences rented via Airbnb, public shower rooms, changing rooms, and toilets. A hidden camera monitoring a cash machine keypad (or any other place where passwords are entered) may be extremely useful for malefactors, too.

First, think who may want to spy on you and why. In some situations, the use of special gadgets may be fully justified indeed. For instance, if somebody wants to track your movements, they may either hire private detectives or gain access to your cloud services, Internet providers, or mobile service providers. However, the most convenient, simplest and cheapest solution for them would be a GPS tracker.

Problem of choice

If, after reading this article, you decide to play superspy, either for malicious purposes or fun, the HackMag Editorial Board strongly advises you against that. In most countries, acquisitions and sales of devices designed for covert information collection are prohibited. Be on the safe side and don’t put yourself at risk.

The next step is to identify the most critical aspect of your information security and focus on it. Remember: you cannot and don’t really need to protect yourself against everything; instead, you have to safeguard what is really important. For instance, a meeting room used by the board of directors, or a zone where a critically important project is developed, or a storage room where you keep something that must never be seen by ill-wishers.

Never forget that social engineering is one of the primary hacking tools. Accordingly, you have to protect yourself against it as well. If you have already defined your ‘secure perimeter’, make sure that persons having access to it are competent and interested in its absolute security. Always keep in mind that nobody pays attention to janitors and technicians – so, they can easily plant a hidden device in your ‘safety zone’. On the other hand, a 100% loyal but disorganized colleague may simply overlook a spying gadget planted in his/her bag or pocket.

Translating theory into practice

Now that you are aware that in many situations, prudence is your best protection against unwanted attention, we can move to technical aspects.

Modern microphone bugs may be less than a memory stick in size. If such a device is planted in somebody’s pocket and simply records information, it can be detected only by a highly sensitive detector and within a very close range. It may have any shape. Therefore, to protect against it, nontechnical methods are required.

Any spying device has strengths and weaknesses. A microphone, even a hard-to-detect one, has two important disadvantages. The first one is its battery. Even if it is very powerful, and the bug activates only during conversations and remains hibernated for the rest of the time, it will discharge sooner or later.

Here the second disadvantage goes: if the device has no transmitter, the malefactor must not only plant, but pick it up as well. Otherwise, all the recorded information would be useless.

Professional bugs are equipped with microphones looking like this, while the majority of simple models available on Aliexpress resemble flash drives

Professional bugs are equipped with microphones looking like this, while the majority of simple models available on Aliexpress resemble flash drives

The situation with video cameras is similar. They may be compact and well-concealed (e.g. cameras embedded into water bottles). But such devices have even more weaknesses than microphones: their battery life is shorter and they always have a lens. It may be very small, but still glares in the light.

There are special detectors allowing to reveal suspicious specks of light, but you may try to search for a camera using a simple flashlight. The darker is in the room, the easier is to detect a speck of light.


Speaking of detectors, it is necessary to note a perennial problem existing on the spying device market. A customer always faces a difficult choice between Aliexpress offering super cheap and super innovative gadgets on the one hand and specialized stores offering devices from renowned manufacturers present on the market for decades on the other hand. Vendors normally put emphasis on two main features: high sensitivity and over-the-top badassery. No one can guarantee though that a device hundredfold more expensive is hundredfold more efficient.
Lens of a pinhole camera available on Aliexpress

Lens of a pinhole camera available on Aliexpress

It is much easier to detect bugs transmitting information in real time. Even the most sophisticated devices cannot circumvent the laws of physics: if data are transmitted, the transmission channel can be detected or jammed.

Most communication channels use the radio frequency range, i.e. Wi-Fi or cellular networks. A planted bug uses either an available guest Wi-Fi network or an access point established nearby – so, you have to pay attention to unknown and powerful signal sources. If a new Wi-Fi network has been recently added to the ones belonging to your neighbors, it may be used by malefactors.

Spying devices may also transmit signals via cellular networks; in that case, you need a radio frequency detector and a wise approach. Prior to the search, turn off all devices using wireless networks to minimize background signals and increase your chance to locate the spy. Then start thorough searches and don’t expect your detector to unveil what is hidden instantly.

How to select a detector

If you are looking for a detector, the impressive price ranges and overwhelming ads may make you dizzy. Be fully aware of what you are selecting and pay primary attention to technical specifications.

For instance, this detector costs $90, its frequency range is 1 to 6500 MHz, and it has a remote antenna and a laser to illuminate cameras. For a nonprofessional device, its specifications and price are pretty good.

A search with detectors does not principally differ from an ordinary examination. Pay attention to suspicious signs: scratches, weird holes, and unknown items. Try to put yourself in the malefactor’s shoes and check places you would use to hide something. Bugs are often planted in light fixtures and receptacles – this allows inter alia to connect them to a power supply. If you see some unknown wires, make sure to check where they lead.

And of course, never permit strangers to plug devices into USB ports of your secure systems. In fact, this advice goes beyond the scope of this article because after getting access to your USB port, malefactors likely won’t need ‘conventional’ spying devices anymore. Be aware that an ordinary USB cable may contain a microphone and cellular antenna for data transmission.

Exotica and esoterics

Now you know the basics, and if your interest (and paranoia) has heightened, let’s examine a few more exciting devices.

Take, for instance, boom microphones. Formally, they aren’t bugs, but can bring the same effect. An acoustic boom microphone may be equipped with a parabolic resonator – such advanced technological ‘ears’ are broadly used by bird watchers. Of course, walls will protect against it, but if you are going to discuss business plans with colleagues outdoors, never forget about such devices.

Parabolic microphones cost only $30-40

Parabolic microphones cost only $30-40

Laser microphones also require a direct ‘hearing line’ to the subject, and this line may be pretty long. But unlike acoustic microphones, they allow to hear what happens in a closed room. The invisible laser ray reads window glass vibrations (according to some anecdotal data, it can even read vibrations of a glass on the table) and reconstructs the sounds.

But don’t worry too much about that: laser microphones are really expensive (tens of thousands of dollars) and require a professional operator. On the other hand, if you attract the attention of secret services, they have plenty of other ways and tools to spy on you.

If you are a fan of expensive ‘toys’, you might be interested in a device called nonlinear junction detector. It emits high-frequency radio waves; upon meeting any semiconductor electronics, they return back reflected in a special harmonized way. This tool makes it possible to detect electronics not connected to power sources, including flash drives and SIM cards. Too bad that such a highly sensitive device often makes false responses and costs thousands of dollars.

An economy class nonlinear junction detector for personal searches costs mere $4000

An economy class nonlinear junction detector for personal searches costs mere $4000

If you still believe that something could be missed and somebody is spying on you, use jamming. You may use an expensive ultrasound white noise generator to dampen audio recording or, alternatively, converse in whispers in a place with numerous noise sources (although vendors of expensive sound recorders claim that their products are able to mitigate any noise).

Jammers for wireless networks and GPS trackers are also available on the market; the latter ones often support the stillness imitation function (the one enabling drivers watched by their employers to detour from the route under the disguise of parking).

An advanced ultrasound noise generator dampening audio recording costs $900 on Amazon.com

An advanced ultrasound noise generator dampening audio recording costs $900 on Amazon.com

Too bad, darkness cannot dampen video cameras – infrared lighting does not turn the night into a day, but still allows to see in the darkness. On the other hand, this feature simplifies the detection of hidden cameras.

A portable mobile telephony jammer in an ironically looking form factor

A portable mobile telephony jammer in an ironically looking form factor

Also, there are plenty of companies offering counter surveillance services. If you are really concerned about such risks, sign a contract with one of them. Regular inspections performed by professionals will definitely raise your security level.


Hidden surveillance devices are a real threat to your security, although a niche one. The use of such tools is justified only when a big catch is at stake – in the modern world, real treasures are kept on servers, not in strongboxes.

Surveillance protection must be supplemented by basic information security practices (e.g. never write passwords on pieces of paper, never plug suspicious flash drives, never leave laptops and smartphones unattended, etc.).

If you suspect that somebody is spying on you, you have a good chance to identify an amateur opponent. But similar to other attack and defense methods, both of you may raise the stakes and employ more expensive and more efficient techniques. The question is whether this is actually justified. If you believe that it is, address professionals equipped with top-notch tools.

And most importantly: if you discover a hidden camera in a residence rented via Airbnb, make sure to notify the service administration of this as soon as possible: you have a chance not only to return your money, but also relocate from a cramped bugged apartment to a deluxe hotel!

3 Responses to “Bug hunt. Spying devices and how to detect them”

  1. Darin Davis

    Somebody’s transmitting voices I can hear them telling me that they’re gonna kill me and they’re watching every move I make how can I find out where they’re transmitting these voices from it’s always the same voice, a girl and a guy and I can hear him plotting against me talking about how I’m gonna die and they’re gonna kill me and they can’t wait till I’m dead please somebody reach out to me for some help I’m scared and concerned

Leave a Reply

XHTML: You can use these tags: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>