Detecting wiretapping in offices - case study

Detecting wiretapping in offices – case study

In the business world, confidentiality protection is becoming increasingly important, especially in the context of intense competition. Our client raised concerns about the possible presence of wiretapping in the office, following a leak of information from a conversation among three members of the board. The client argued that such a situation could not have occurred without external wiretapping devices. Following initial discussions, we undertook analysis and actions aimed at identifying and eliminating potential threats to data confidentiality.

Description of the investigated object

The office space is located in an industrial building from the late 1970s and 1980s, which has been adapted for office use. The company’s management decided on this solution mainly for logistical reasons – the building is situated on the same plot as the company’s production hall and warehouse. The immediate surroundings consist of a former industrial district in one of the largest Polish cities, which is undergoing revitalization and transforming into office and service areas as the city develops. There are many other office buildings, warehouses, old industrial buildings, and one hotel in the vicinity.

Technicians’ actions

Technicians conducted a multi-stage inspection of the entire premises in accordance with the adopted methodology. The equipment used in the examination allows for the detection of listening devices, audio recorders, internet cameras with recorders, and other electronics. The detection device kit was selected so that it does not matter whether this electronics is turned on or off to be detected.

Effect of wiretapping detection

The technicians conducted routine examinations of the areas indicated by the client, but they did not detect any surveillance devices. However, a potential issue arose during the test of acoustic barriers. The concerning result of this test prompted the technicians to physically inspect the structural elements of the premises, during which they noticed that modern partitions dividing the open space into smaller rooms only reached the level of the suspended ceiling, above which there was nearly a meter of space to the actual ceiling. There were old suspended lamps and cables of unknown purpose. The fire installation and ventilation ducts were added during the modernization of the facility in attempts to adapt it to current standards. Above the level of the partition walls and below the suspended ceiling, the rooms were divided with makeshift gypsum board partitions, resulting in practically zero acoustic insulation. Being in the rooms adjacent to the hall where important conversations took place, one could hear or record everything. Moreover, under favorable conditions (quiet), conversations from the hall could be heard throughout a large part of the office. The technicians also noted the risk of external surveillance stemming from surrounding buildings of other offices and even a hotel, whose windows directly faced the office windows, posing a real risk of using laser microphones or recording meetings with a camera.


During the described assignment, the technicians performed all tasks with due diligence; however, they did not find any wiretapping .

Explanations could be as follows:

  • The wiretapping was present before, but it has been removed now (relevant information was acquired and utilized, leading to the detection of the problem).
  • Confidential conversations are not truly confidential (due to ineffective sound insulation of the rooms or lack of control over adjacent rooms to those where sensitive conversations are held).
  • Wiretapping is conducted from outside using, for example, a laser microphone.
  • Many others.

When the result of a counter-surveillance investigation fails to determine the location of a leak and that its source is a technical means, it still provides valuable information. After receiving guidance from technicians during the examination and reviewing the report, the client, with a broader understanding of the situation, can plan further actions and changes in the company’s operations. The recommendations included in the report address a wide range of risk factors encountered during the investigation and provide value in preventing similar and other crises in the future.

In this case, the client found, among other recommendations, points regarding securing window panes from external surveillance possibilities, such as using random noise emitters, i.e., vibroacoustics, and applying specialized film to windows to prevent laser beams from penetrating the room.

Old industrial buildings and office buildings may be attractive due to lower rental prices and often very good locations, but it should be remembered that in old walls, more attention should be paid to a greater number of issues than in a newly built office building equipped with the latest technological advancements. The drawbacks of old buildings can be the cause of troubles, especially if their harmful potential is not recognized early and neutralized with appropriate procedures or technical solutions. Counter-surveillance investigation is not only an action taken after a specific incident, leak, or suspicion of espionage but also serves as part of a broader information security audit, i.e., one of the steps towards eliminating the causes of the problem.

Author: Michał Nosowski

*For the respect and safety of our clients, all sensitive data has been anonymised for publication purposes.

We also invite you to read our other case studies:

Scroll to Top