How to detect eavesdropping at work: where to look, how to prove it, where to report

Eavesdropping at work is not a movie scene. It is a 40-dollar GSM bug in a power strip under the conference table. A leaked quote, a client list or a conversation about layoffs costs more than every detector put together. This guide shows how to detect eavesdropping at work: what a bug looks like, where to look for it in an office, how to check a room yourself and when to call specialists. Separately: how to prove eavesdropping at work and where to report it.

What a bug at work looks like

A bug rarely looks like a bug. In offices you most often find:

• A power strip or an extension cord with a built-in GSM module. Power forever, and a strip under the table surprises nobody. From the outside it differs only in weight and sometimes an extra slot.
• A USB charger or a power adapter in the socket. It looks like an ordinary charger, with a 1-2 mm hole for the microphone and sometimes a SIM card under the housing.
• The wall socket itself. A module behind the frame, powered from the mains. Fresh marks on the screws and a frame in a different shade give it away.
• A pen, a USB stick, a wall clock, a smoke detector. Housings from ready-made kits, battery powered for a few days or wired to the mains.
• A conference phone or a speaker. The microphone is already there; all it takes is a module that listens to it.
• A WiFi camera in a motion sensor or a router. Live video and audio in the eavesdropper's app.
• A voice recorder. Transmits nothing, records to a card for dozens of hours. Somebody has to come back for it: usually cleaning staff, a service visit or the colleague at the next desk.

A bug is a coin-sized board with a SIM card or a WiFi module. Everything else is a housing meant to fool the eye.

How to check whether a room is bugged: where to start

Signals that should worry you:

1. Information from closed meetings is known to people who were not there: a competitor, a contractor, an employee.
2. New objects have appeared in the room: a power strip, a charger, a clock, a plant, a gift from a client.
3. Someone had unsupervised access to the room: air-conditioning service, network installation, after-hours cleaning, a former employee with a key.

Before you search, two rules. First: do not discuss your suspicions in that room or on a phone that is lying in it. Second: decide whether you want evidence for a case or just peace of mind. If evidence, document everything with photos from the first step and act with a witness present.

How to find and locate a bug in an office: the list of places

How do you locate a bug when the office has twenty rooms? Start where decisions are made. A bug is planted close to conversations, close to power and out of sight. In an office check in this order:

1. The conference room: power strips and extension cords under the table, the underside of the tabletop, the conference phone, the TV and its remote, the speakers.
2. The boss's office and the finance department: the desk lamp, chargers, sockets behind the desk, frames, flower pots, blinds.
3. The suspended ceiling and ventilation grilles above the meeting spot. One tile to lift, zero traces.
4. The printer, the router, the switch, the TV box. Electronics inside electronics surprises nobody, and the power is there.
5. The company car: under the seats, the glove box, the OBD port (GPS trackers with a microphone), the cigarette lighter socket.
6. Things brought in from outside: trade-show gadgets, mugs, power banks, USB sticks from contractors.

Look for fresh dust on the edges, screwdriver marks, extra wires and 1-2 mm holes that have no reason to be there.

How to detect a bug in a room: methods and equipment

What works:

1. A physical search with the list of places. Method number one; it also finds voice recorders, which no detector will show.
2. The device list in the company WiFi. Every IP camera or microphone connected to the network is in the router panel or in a network scanning app. An unknown device named something like "IPC", "Cam" or "ESP" is a lead. In an office with its own IT department, ask for an export of the list from the last few weeks.
3. A lens finder. A camera must have an opening for the lens. The reflection of the lens is visible in the detector's viewfinder from several meters away, including inside a smoke detector or a clock.
4. A WiFi detector. Shows devices transmitting in the 2.4 / 5 / 6 GHz bands, including those connected to a stranger's hotspot that are not in the company network.
5. A wideband RF detector. Catches radio and GSM transmitters while they are transmitting. In an office with dozens of phones and networks, sweep after hours with your own equipment switched off.

What is a myth: interference on FM radio, "crackling" in the phone, magnetometer apps, listening to silence. Modern bugs work on LTE and WiFi; nothing crackles and nothing beeps.

A full description of bug types and a step-by-step procedure is in the guide Bugs in your home: how to find a listening device. The same methods work in an office.

When to call a counter-surveillance (TSCM) firm: when a trade secret, a court case or a suspected bug in the installation and cabling is at stake. A specialist uses a spectrum analyzer, a non-linear junction detector and a thermal camera, checks the network and finishes with a report that counts as evidence. What such an audit looks like is described in Counter-surveillance in business.

How to prove eavesdropping at work

Finding the bug is half the job. The other half is evidence that survives in court or in a conversation with the board.

1. Do not touch it and do not remove it. Take photos and a video where it was found, with the surroundings and the date.
2. Call a witness, ideally two. Write a short note: who, when, where, what is visible.
3. Secure the CCTV recording and the list of people with access to the room over the last weeks.
4. Do not confront the suspect. Every warning gives them time to remove the rest of the devices.
5. Report to the police if you want criminal proceedings. The police secure the device and can identify the owner of the SIM card.
6. When the stakes are high, order a TSCM audit. A report with signal parameters, photos and a protocol is evidence that "it was just a clock" will not shake.

Is eavesdropping at work legal? Penalties and where to report

In Poland an employer may use video monitoring, but only for defined purposes and after informing employees (Art. 22² of the Labour Code). Recording employees' conversations without their knowledge is a different matter: the data protection authority considers it inadmissible, and planting a listening device to obtain information one is not entitled to is a crime under Art. 267 § 3 of the Penal Code, punishable by up to 2 years in prison. The same applies to an employer, an employee and an outsider. Most countries have equivalent rules.

Where to report eavesdropping at work in Poland:

• The police or the prosecutor: a crime under Art. 267 of the Penal Code, prosecuted at the victim's request.
• The Personal Data Protection Office (UODO): when the employer is the one listening.
• The National Labour Inspectorate (PIP): breaches of the Labour Code on monitoring.
• A civil court: violation of personal rights (Art. 23 and 24 of the Civil Code) and compensation (Art. 448). A claim for damages needs the evidence from the previous section.

Frequently asked questions

How do I recognise a bug when I do not know what I am looking for? Look for a 1-2 mm hole with no purpose, a SIM card under the housing, an object that is heavier or warmer than it should be, and things that were not in the room before.

Can a company laptop be bugged? Corporate device-management software is legal if the employee has been informed about it. Secretly switching on the microphone without the user's knowledge is eavesdropping. That is checked by the IT department or a specialist, not by an app from the store.

I found a bug at work, what now? Do not remove it, photograph it, call a witness, report it to the police. From the evidence section: points 1-5.

How do I check whether my office or room is bugged, without equipment? The list of places in this article plus the device list on the WiFi network. That catches most bugs in power strips and chargers and every camera on the company network.

What is the penalty for eavesdropping at work? In Poland up to 2 years in prison under Art. 267 § 3 of the Penal Code, plus civil liability for violation of personal rights.