Modern methods of intercepting information.
MODERN METHODS OF INTERCEPTING INFORMATION
Victor Iksar
“Information (from the Latin informatio — explanation, presentation) is data transmitted by some people to other people orally, in writing or in some other way (for example, with the help of conventional signals, using technical means, etc.), as well as the process of transmitting or receiving this information.” Great Soviet Encyclopedia, 3rd edition, volume 10, page 353.
The importance of what lies behind this simple and understandable word, many of us have begun to realize only now, when “primitive” capitalism with its relatively free, but absolutely brutal competition has come to Russia. In this rapidly growing struggle for money and power, a struggle that recognizes neither laws nor rules, information is the most important weapon. One phrase dropped by you and accidentally (and more often not accidentally) overheard — and you can lose a profitable deal, go bankrupt, become the object of blackmail. Moreover, all contract killings are committed on the basis of carefully researched information about the future victim.The most frequent customers for covert collection of other people's information are: competing firms and individual competitors; sales and market research departments of large companies; industrial espionage specialists; employees trying to get a lucrative position in their firm; company executives; unscrupulous partners; representatives of the press; government agencies.
The most common targets of espionage are individuals who: are involved in a trial; are suspected of committing crimes or concealing income; are planning to get married or divorced; are running for office; are executives of large companies, lawyers, doctors, law enforcement or judicial officers, or software developers; are actively involved in politics; are due to receive large insurance; are engaged in secret work; have a large income.
The most common targets of espionage are firms that: are involved in litigation; are undergoing reorganization or are on the verge of closing; are involved in fashion, automobile manufacturing, advertising, marketing, advanced materials development, micro- and nanoelectronics, communications and information processing, biotechnology, aeronautics, energy, and environmental protection; are involved in long-term projects; are planning to purchase expensive equipment or real estate or enter into another major transaction; are preparing to reduce staff; owe their success to the use of secret recipes or technologies or are preparing to release new products.The direct executors of orders for covert collection of information are most often former employees of the relevant government organizations or simply specialists in industrial espionage who are ready to use their experience for a fee, private detectives, employees of the company itself recruited for one reason or another, or even just amateurs. Experienced specialists rarely penetrate a company illegally; they usually work by posing as officials, employees of a telecommunications or electric company, or by being hired by the company as auxiliary personnel, allowed into the company's premises outside of working hours.
The main motive for hunting for other people's information is the desire to get rich or gain power. So if knowing your secrets can increase someone's wealth or power, you are potentially, and perhaps already actually, a target of espionage. Establishing the fact that you are a target of espionage is not easy. To do this, you need to use the services of counterintelligence specialists, but there is one universal sign that should make you wary: your information, even the most insignificant, inexplicably becomes known to people who do not have access to it.
There are many ways to get hold of other people's personal or business secrets, they are carefully worked out, but few people know.
For ease of presentation, we will divide all information into two main categories: verbal information and non-verbal information. Verbal information is various pieces of information expressed by means of language (written or spoken). Non-verbal information does not convey any specific content, but indirectly indicates, confirms or refutes a particular fact. These are movements, meetings with someone, places visited, behavior during these, etc. (for example, a secret meeting with a representative of a competing company).
Both categories of information are divided into two types: the first is (using American terminology) “soft” information, i.e. information, the carrier of which is a field (acoustic or electromagnetic). Such information lives literally for moments; once produced/voiced, it disappears and cannot be reproduced again. In simple terms, “soft” information is information contained in the words you have spoken (on the phone or in a personal conversation), or your current actions.
The second group is “hard” information, i.e. information recorded on some material medium (paper, magnetic tape, etc.). Such information, if not specially erased, can exist as long as the medium itself exists. This includes various documents, magnetic, film and video recordings, etc.
When carefully developing an object, all categories and types of information are usually collected.
Let's start with an analysis of the methods and means of intercepting «soft» verbal information, since in most cases it is the object of the closest attention. Firstly, because it provides specific information (unlike both types of non-verbal information). Secondly, unlike «hard» verbal information, it has significantly more specially developed means that allow you to obtain it quickly, with less risk for yourself and, as a rule, without significant costs. Thirdly, it is much more extensive and varied in terms of the information obtained, and finally, it is the most important source of personal information (you are unlikely to be able to find a document on a company letterhead that would describe, say, the boss's extramarital affairs).
Eavesdropping
The simplest way to intercept information is ordinary eavesdropping without the use of special equipment or with the use of relatively simple devices.
Situations are still common when: visitors in the reception area can quite clearly hear everything that is happening in the office of an official; in the smoking room, company employees, not paying attention to the presence of strangers, discuss important problems; in the summer, meetings, including on the lower floors of offices, are held with open windows or vents. What does it cost an experienced specialist, who finds himself in the office for an “official” reason, to remember what he heard or record it on a dictaphone? Often, important business and personal issues are discussed in cafes, restaurants, and even in a state of intoxication. Knowing your favorite places, it is not difficult for a specialist to be at the next table and hear your revelations or bribe a waiter to plant a dictaphone or simply remember fragments of your conversation.
To record conversations, they often use voice recorders equipped with an acoustomat (automatic switching off system during pauses in conversation) and a tape speed regulator, hidden in pockets or packages that are taken away after visiting places of interest. They are often built into various objects, such as briefcases, watches, etc. The tactics of using these devices are quite simple, but effective: a briefcase is “absentmindedly” forgotten in an office or reception area, and watches are given to people whose premises are accessible to trusted people (to change cassettes) — cleaners, security guards, watchmen.If the conversation of interest takes place outdoors, they resort to such a technique as unobtrusive alternating strolling within earshot of two or more impersonal «stompers», who seem to be doing their own thing, but in fact are listening to your conversation or recording it on portable dictaphones. The full conversation is then compiled from the recordings of these several people.
Such a cheap and safe method as drilling holes in the wall of an adjacent room and eavesdropping or recording the conversation through them is quite widely used.
Another common method of eavesdropping is based on the fact that the impact of an acoustic signal on the surface of solid bodies causes microvibration in them. It can be implemented using the simplest improvised means, for example, a glass or goblet that happens to be at hand, the rim of which is pressed tightly against the wall, and the bottom is close to the ear. A very popular tool for this is an ordinary medical stethoscope, applied to the opposite side of the wall. Sometimes, to improve the quality of interception, it is equipped with a suitable microphone capsule connected to a sensitive amplifier.
Higher quality of interception is ensured by attaching a miniature vibration sensor to the back of the barrier behind which the conversation is taking place and then converting the signal received from this unique microphone. This method allows information to be collected through reinforced concrete walls up to 100 cm thick, doors and window frames with double glazing. The advantage of vibration sensors is that, unlike microphones, they can be installed not in the premises themselves, which are often carefully guarded, but in neighboring ones, to which security services pay much less attention.
Acoustic vibrations, exciting vibrations in water supply and heating pipes, cause hydroacoustic signals in the liquid located in them. Theoretically, it is possible to intercept the information being discussed within the building using a hydroacoustic sensor, and, according to available data, such systems have been tested. However, the quality of interception was low, since the sensor picked up conversations in all rooms, and the noise level in the water supply is too high. So there is no particular reason to fear such interception yet.
Some recommendations for counteraction
1. Compliance with the rules for discussing confidential information (absence of strangers, closed windows, etc.).
2. Compliance with office access rules (checking and photocopying visitors' documents, checking for orders to perform work in or around the office, organizing the escort of repair service representatives, etc.).
3. Periodically inspecting hard-to-reach areas of the premises for holes (walls in corners, behind furniture, at baseboard level, on the ceiling near lighting fixtures).
4. Equipping soundproofed interior spaces for negotiations.
Interception of information using electronic means
Among all the variety of electronic interception methods, wiretapping of telephone conversations occupies a special place, since the telephone line is the most common and the most unprotected communication channel. Electrical signals are now, as they were a hundred years ago, transmitted over wires in the open, and wiretapping a telephone line has become a simple and cheap matter in our time. It can be said with complete confidence that if someone is interested in someone else's information, the first thing they will most likely do is start monitoring the telephone conversations of the source of this information, since this method of obtaining information requires minimal costs.
Direct connection to the telephone line is made either at the appropriate PBX (using a bribed employee), or by connecting to this line at any point between the telephone set of the object of interest and the PBX. Most often, this is done at the distribution box closest to the set. The eavesdropping device is connected to the line either in parallel or in series, and a branch is made from it to the interception post, which can be equipped with various devices: from a digital recorder capable of registering only the numbers dialed from the monitored telephone, or the numbers from which the incoming signal is received, to a tape recorder that allows recording the content of all conversations conducted on a given line. To reduce the possibility of detecting the interception post, free pairs of telephone cable are often used as a branch (in this case, the post itself can be equipped quite far from the intercepted telephone).Direct connection is the simplest, cheapest and easiest to implement method of wiretapping telephone conversations. However, it has a number of tell-tale signs. Thus, a poorly executed connection is manifested in clicks and volume drops that occur during a conversation on the monitored telephone. In addition, the tap is often easily detected and traced to the interception post, which ultimately allows you to find out who is conducting reconnaissance.
In order to increase the secrecy of interception, inductive connection to the telephone line is practiced. It is based on the principle of electromagnetic induction in a nearby conductor. With this connection, one of the wires of the telephone line is either wound around a miniature multi-turn coil with a ferromagnetic core, or such a coil is placed near this wire. The terminals of the resulting improvised transformer are connected to a low-frequency amplifier, a dictaphone or a microtransmitter.
In another version, inductive interception is carried out using an electromagnetic detector. If this detector has sufficiently high characteristics, then interception can sometimes be carried out at a distance of 10-80 cm from the telephone line, located next to the controlled device.
An even more sophisticated and still little-known method is the use of induction in the adjacent pair of the same telephone cable in which the monitored line is located. Interception is carried out by changing the connection scheme of the telephone line of the monitored telephone so that its signal induces a similar signal in the telephone pair of the interceptor.
The general advantage of inductive connection is the absence of unmasking direct contact with the telephone line being tapped, so it is the safest from the point of view of accidental detection of the fact of interception. The disadvantages of this method are the rather low level of the induced signal, which requires additional amplification, as well as the high sensitivity of the intercepting device to extraneous electromagnetic radiation.
To avoid interference in the telephone line, which would unmask the inductive connection, the method of radio transmitting connection to the telephone line is widely used. In this case, the intercepted conversations are transmitted to the interception post using miniature radio transmitters or «radio bugs».
Just as in the case of a wired connection, a “radio bug” can be connected to a telephone line either in series or in parallel. In the first variant, it is “wedged” into a break in the line and fed with its own current, which provides the “bug” with an unlimited working resource, although in this case there is an unmasking decrease in voltage in the line. In the second variant, a miniature transmitter with its own power source is connected in parallel to the line. Such a connection complicates its detection, but requires periodic replacement of the power source. Structurally, all these devices are low-power, mainly transistor VHF generators (27-900 MHz), modulated by current surges that occur in the line during a telephone conversation. For such interception, “bugs” operating at frequencies of the broadcast range (66-74 and 88-108 MHz) are often used, which makes it possible to receive the signal they transmit using ordinary VHF radio receivers at a distance of up to several hundred meters.
If possible, “radio bugs” can be installed directly into a telephone set. Thus, in the West, “radio bugs” built into the back of a carbon telephone microphone are produced and sold. Installing such a bug into a telephone takes a matter of seconds — it is enough to replace the microphone of the monitored telephone.
The advantage of a radio transmitting connection to a telephone line is the absence of obvious unmasking taps leading to the interception post, which can now be located anywhere within the effective reception zone.
It is useful to know that many telephones, especially those with push-button dialing, are themselves sources of parasitic radio emissions, so that conversations conducted on such telephones can be intercepted at a frequency of the long-wave range (about 150 kHz) at a distance of 100-200 meters.
Using a telephone to listen to conversations indoors
The telephone has another disadvantage from the point of view of security: the presence of devices that work as a receiver and transmitter (microphone, membrane, bell chain). Its location in a place convenient for interception, the presence of ready-made wiring to carry the signal to the interception post, the power supply provided by the telephone system itself, make the telephone a ready means for intercepting all conversations in the premises where it is installed, even when the telephone receiver is on the hook. To make the telephone a permanently transmitting device, it remains only to slightly modify it or change the connection scheme.Wiretapping through a ringing circuit is based on the fact that when a telephone receiver is hung up, the electromagnetic ringing of the device remains connected to the line. The ringing has reversibility or a “microphone effect”, which is expressed in the fact that the mechanical vibrations of its moving parts, caused, among other things, by voices sounding in the room, cause an electric current of low amplitude in it, which, however, is sufficient for this signal to be processed and the sound component to be extracted from it. Such processing, as a rule, is carried out not too far from the monitored device. The described interception scheme is always available to an intruder, since the ringing is on the other side of the receiver switch on an always accessible telephone line. In passing, it should be noted that in a similar way it is possible to intercept a signal not only from a telephone, but also from an apartment bell.
The disadvantage of this method is that such interception is very easy to neutralize if you connect two silicon diodes paralleled in the opposite direction in series with the bell. And even easier — by disconnecting the phone from the network.
Another option for listening to telephone conversations is to use high-frequency pumping. To implement this, a high-frequency generator, adjustable in the range of 50-300 kHz, is connected to one of the telephone line wires relative to some common mass (sewage pipes, heating, etc.). By smoothly adjusting it, the frequency of its resonance with the telephone is found and left to work at this frequency. When the telephone receiver is put on the hook, external high-frequency oscillations penetrate through the design elements of the device into its circuit and are actively modulated by a microphone that reacts to sounds in the room. The signal carrying information is sent through the telephone line wire to the interception post, located, if possible, within several tens of meters from the monitored device, processed and recorded. An effective means of combating this type of interception is a capacitor connected in parallel to the microphone.
It should be noted that high-frequency pumping also allows information to be retrieved from household and special equipment (radio points, electric clocks, fire alarms), if it has a wired exit from the room.
Another method of drying is implemented by installing a device in the device that blocks the handset switch after it is removed. The tactics of using this method are as follows: with the device installed, the attacker calls the number of the controlled telephone. The owner of the telephone picks up the handset, but upon hearing silence from the calling party, hangs up the handset. The device that is triggered blocks the disconnection of the handset until the listener on the opposite end hangs up his handset as well.
The disadvantage of this method is that it can be accidentally detected by anyone who calls the same number, and also the monitored line can be unexplainedly busy for other subscribers.
A more covert method is to install a device in the phone that is activated by a special code through any external telephone. In a simplified version, a small resonant relay tuned to a certain frequency is introduced into the telephone circuit. The eavesdropper dials the number of the monitored phone from any other phone, including a long-distance one, and brings a portable sound emitter (beeper) to his receiver, the tone signal of which corresponds to the frequency of the relay. The relay quickly turns off the ringer of the device and switches the handset to the on state, allowing the caller to listen to all conversations in the room. The device operates independently of the phone itself and, as a rule, requires an additional telephone line. Such devices are widely sold in the West for home monitoring.
The described scheme has several modifications, in particular, a complicated code (to complicate the accidental detection of the fact of interception), the use of a special amplifier and microphone (to improve the quality of the signal).
It should be noted that sometimes the bell may ring briefly before the resonant relay switches it off. Such a shortened ring may be a possible sign that the telephone is being used for eavesdropping. An additional warning sign is the busy working line during periods of time when it should be free.
The most covert option, now widespread in the West, is when a device that blocks the switch of a telephone handset is connected somewhere on the line simultaneously to the monitored telephone and a specially rented telephone, the pair of which is in the same telephone cable. The spy calls the number of the phone he rented, thereby activating the device, which switches the handset of the monitored telephone to the on state and automatically connects the monitored line to the rented one. This method is more covert and allows you to listen in on conversations in a room from almost anywhere in the world.
“Attacks” on computerized telephone systems
Recently, computerized telephone systems (PBX and office mini-PBX, controlled by a computer) have become the object of close attention of interception specialists. In such systems, all telephone connections are made by a computer in accordance with the program embedded in it. In general, an “attack” on such a telephone system consists of the fact that intruders, using well-established methods, remotely penetrate the local computer system or the control computer itself and change the program by which it makes telephone connections or provides subscribers with access to the system. As a result, they are able to intercept all types of information exchange carried out in the controlled system from their telephone. At the same time, it is extremely difficult to detect the fact of such interception.
Some recommendations for counteracting the interception of telephone lines
Common signs of a possible hidden connection to a telephone line are:
• strange sounds in the telephone receiver, sudden changes in volume during a conversation, the appearance of clicks or rustling sounds;
• your phone rings frequently, but the calling party is silent or you hear a high-pitched tone (your phone may be on permanent broadcast mode);
• you hear some sounds coming from the hook of the phone (your phone may be on permanent broadcast mode);
• traces of a break-in or other signs of entry into the premises (for example, the front door lock suddenly starts acting up), as a result of which nothing was stolen (such entry may have been undertaken to install a bug or change the telephone connection scheme);
• an unexpected visit from “employees” of the telephone or electrical network, plumbers to carry out work that you did not order (this is a very common technique for gaining access to the premises of interest);
• closed vans are very often parked near your home or office for a long time (interception posts are most often equipped in such vehicles).
The most reliable method of counteracting interception of information from telephone lines is to comply with the general rules of confidential information exchange until it is completely stopped. In case of serious suspicions, it is necessary to contact competent organizations to conduct an inspection of the premises and identify listening devices. The specialists called in can advise which of the methods of active counteraction to interception is advisable for you to use. Among these methods, the most common are:
1. Installing a voice signal encoding device (scrambler) on the telephone, which provides the highest level of signal protection along the entire telephone line. It resists any interception equipment, since it requires time to determine the encoding algorithm. This method, however, is very complex and expensive, requires the installation of compatible equipment at all subscribers participating in closed communication sessions, and causes time delays for synchronizing equipment and exchanging keys at the beginning of a telephone exchange and between the moment of transmission and the moment of reception of a voice message. In addition, it cannot resist the interception of voice information from premises in the intervals between negotiations.2. Using telephone line analyzers, which signal a possible connection based on measuring the electrical parameters of the telephone line or detecting extraneous signals in it. However, such devices are characterized by a high frequency of false alarms, since existing telephone lines are far from perfect and cannot detect some types of connections.
3. Use of one-way speech maskers, which, when receiving an important message from a remote subscriber, feed an intense masking noise signal into the telephone line, which spreads along the entire length of the communication channel and is filtered at the input of the receiving device. Such devices provide a fairly high degree of protection, but only for incoming messages. To protect outgoing messages, a similar device must be installed at the opposite end of the line. In addition, the use of maskers produces strong noise in the receiver of the subscriber transmitting the message, and does not prevent the interception of speech information from the premises in the hang-up mode of the telephone line.4. Use of active jamming devices designed to protect telephone lines from virtually all types of eavesdropping devices. Such devices mix various types of additional signals into the line or change its standard parameters, followed by compensation for all changes made when a signal is sent to the owner's telephone set. As a result, instead of useful information, the intruder hears only noise. The disadvantage of these devices is that they protect the telephone line only in the section from the device itself, to which the standard telephone set is connected, to the city PBX and cannot prevent the interception of information from the unprotected line of the opposite subscriber and from the PBX itself.
Despite such serious shortcomings, jamming devices have received, perhaps, the greatest distribution among all other types of equipment designed to protect the telephone line. One of the reasons for this popularity is the need to purchase only one device to protect your «shoulder» of the telephone line, and this is a significant saving of money.
5. Installation of passive protection devices in the form of filters and other devices designed to disrupt certain types of wiretapping of premises using a telephone line in hang-up mode. Such devices are effective in preventing the interception of speech information using the HF pumping method, prevent the possibility of eavesdropping through the ringing circuit and using microphones that transmit speech information over a telephone line in the long-wave range. The disadvantage of these devices is that they do not protect against the rest of the variety of interception systems.
Finally, do not forget that the simplest way to neutralize all methods of wiretapping premises via a telephone is to disconnect it from the line, but it should be remembered that any telephone can have a built-in “radio bug” that operates regardless of the telephone line.
As for the methods of protecting computerized telephone systems, the most common of them are:
• replacing a regular modem connecting the PBX to external lines with a special one that allows access to the system only from authorized numbers;
• ensuring the protection of internal programming terminals;
• thorough verification of the reliability of the employee performing the duties of the system administrator;
• surprise checks of PBX software settings;
• tracking and analysis of suspicious calls.