Welcome back, aspiring cyberwarriors!

Wireless security monitoring in the 2.4 GHz spectrum often depends on active probing, which can not only make the monitoring infrastructure vulnerable to attackers but also clutter the radio frequency environment. On the other hand, taking a passive approach by listening without transmitting allows security teams to detect malicious wireless activity more discreetly and reliably.

To put this idea into practice, the project Travel WiFi Canary was developed. This system serves as an early-warning mechanism using ESP32 microcontrollers. By operating the Wi-Fi radio in promiscuous mode, the device passively captures raw IEEE 802.11 management frames and traffic patterns. This helps identify potential threats such as deauthentication attacks, beacon spam, rogue access points often referred to as Evil Twins, and unauthorized probe requests. Eventually, it provides comprehensive insights into the wireless environment, enabling you to act proactively rather than reactively.

In this article, we will guide you through configuring, flashing, and running Travel WiFi Canary on the LilyGo T3 V1.6.1 development platform. Let’s get rolling!

What is Travel WiFi Canary?

The Travel WiFi Canary is a project that turns a low-cost ESP32 microcontroller into a passive 2.4 GHz threat-detection device. It operates continuously by alternating between active network enumeration and passive promiscuous packet capturing across specified channels.

At its core, the device’s Wi-Fi chip listens directly to raw radio signals passing through the air rather than connecting to a specific network.

When a wireless signal arrives, a fast automated responder checks the basic structure of the incoming data instantly. It identifies network management signals, such as connection requests, disconnection commands, or nearby network announcements, and separates them from standard web traffic.

To handle intense bursts of wireless activity without getting overwhelmed or missing crucial information, the chip places these flagged security signals into a temporary holding queue. This allows the main system to process and analyze the data safely in the background while keeping the hardware radio free to capture new incoming signals without interruption.

The central intelligence of the project relies on a dynamic confidence-scoring engine rather than rigid binary alerts. As the system processes the ring queues and periodic active scans, it evaluates detected anomalies against a local memory table built during the startup baseline phase.

Active scans check nearby Access Points for structural security violations. If an Access Point using an encrypted baseline protocol like WPA2 or WPA3 is detected operating without encryption, the system identifies an open clone attack. Security downgrades, unexpected vendor prefix mismatches on familiar SSIDs, or sudden disappearances of legitimate Access Points during an active open broadcast instantly contribute points to the global confidence score.

Simultaneously, the passive sniffer thread drains the lock-free queues to detect airborne attacks. Deauthentication frame floods are monitored over rolling time windows, assigning score penalties if threshold limits are breached by single sources or broadcast addresses.

The sniffer also inspects the payload fields inside beacon frames to detect Pwnagotchi signatures, parsing JSON structures hidden in vendor tags to determine if the device is operating in an active attack state.

All calculated points feed into a unified state machine. Aggregate scores between zero and two keep the device in a normal state, scores between three and five push it into a caution state, and scores of six or higher escalate the device into an active alert state.

To prevent temporary radio noise or brief packet anomalies from causing permanent alarm states, a background timer executes a score decay routine every minute. This routine gradually reduces the aggregate threat score over time, allowing the system to automatically transition back to a normal state once threat vectors clear the area. Hardware outputs, such as status LEDs or connected display controllers, continuously mirror the internal state variable to provide real-time visual monitoring.

What is LilyGo T3 V1.6.1?

The Travel WiFi Canary was initially made for the M5Stack Atom Lite development board. However, in this demonstration, I will test it on the LilyGo T3 V1.6.1.

The LilyGo T3 V1.6.1, also called the TTGO T3 LoRa32 V1.6.1, is an open-source development board designed for Internet of Things (IoT) projects and long-range RF communication. It has an ESP32 chip that allows for packet sniffing and Wi-Fi scanning. It gives us all the necessary functionality for wireless threat detection required by the Travel WiFi Canary project.

Getting Started with Travel WiFi Canary

The best way to flash the Travel WiFi Canary is by using Visual Studio Code along with the PlatformIO IDE extension. The installation process is fairly simple, so let’s move on to the next step, which is cloning the repository. I will use the modified version designed for the LilyGo T3 device. Here’s the command to do that:

kali> git clone https://github.com/AirClick-Code/esp32-wifi-canary.git

Next, connect your LilyGo T3 V1.6.1 to your computer using a data-capable Micro-USB cable. In Visual Studio Code, click on the PlatformIO status bar at the bottom and select env:esp32dev. Then, you can either click the checkmark icon in the status bar or press Ctrl+Alt+B to compile the firmware.

Once that is complete, click the right arrow icon in the status bar to start the upload process. PlatformIO will automatically detect the serial port, trigger the ESP32 to enter bootloader mode via auto-reset circuitry using the DTR and RTS lines, erase the necessary flash sectors, and upload the binaries seamlessly.

After the upload is complete, you can monitor the device with the built-in command:

pio device monitor -b 115200

At this point, the state machine and scanning engine are fully operational. During its initial scan, it detected seven nearby access points, recording their SSIDs, BSSIDs, signal strengths, channels, and encryption methods in memory.

Now, let’s simulate an open clone of a known encrypted network. The README file provides the following instructions:

I created a Wi-Fi access point from my phone with the same name as the network to which my system is connected, but without a password. Let’s observe how the WiFi Canary responds.

The script successfully identified the clone and granted 4 points to the score, changing the state to caution. The rogue open clone remained active in the following 20-second scan with a strong RSSI, adding another 4 points, which brought the total score to 8 and changed the state to alert. At the 310-second mark, the decay timer activated, decreasing the score from 8 to 7. However, since the score remained above the SCORE_ALERT threshold of 6 or higher, the system continued to maintain its alert state until the threat was resolved and the score naturally decayed back to zero.

Limitations

Despite the benefits of confidence scoring in reducing unexpected alerts, the possibility of false positives still exists. This is particularly true in enterprise networks, multi-node mesh setups, and crowded public venues, which can display behaviors that resemble attack patterns. On the flip side, false negatives may arise if a skilled attacker impersonates a legitimate BSSID while carefully adjusting their transmission power to fit in with normal signal strength variations, thus evading detection.

The limitations of the physical hardware create additional coverage boundaries. Passive detection of deauthentication relies heavily on the distance from the receiving device, meaning that low-power or far-off transmitters may be beyond the reach of the antenna. Furthermore, monitoring is confined solely to the 2.4 GHz spectrum, leaving the 5 GHz and 6 GHz bands completely unmonitored.

Lastly, the design of the radio architecture leads to a temporary gap in scanning whenever the chip switches between promiscuous packet sniffing and active environment scanning, resulting in a three-second blind spot where airborne deauthentication bursts can go unnoticed.

Summary

For many travelers and remote workers, understanding whether the Wi-Fi around them is secure is crucial. Private messages and sensitive information can be easily compromised when malicious actors set up fake hotspots or disrupt local connections. A device like the Travel WiFi Canary can continuously monitor the airwaves and alert you the moment a wireless attack is detected.

This device uses active Wi-Fi scanning and passive signal listening to find threats in real time. It constantly checks nearby networks against a trusted standard to spot fake open hotspots, duplicate routers, or security issues. At the same time, it listens for harmful activities like deauthentication attacks or rogue scanning tools. When it detects a threat, it raises a danger level with an internal scoring system and triggers a clear visual alarm. This alerts you immediately, giving you a warning before your devices may face any risk.

If you’re interested in improving your knowledge of wireless security, take a look at our Wi-Fi Hacking training. This course will guide you on how to assess the security of wireless networks and equip you with modern strategies to protect them effectively.

The post Building a Pocket Wi-Fi Threat Detector first appeared on Hackers Arise.

A Storm-2945 campaign layers device code phishing onto hijacked hotel Wi-Fi to bypass MFA on Microsoft 365 accounts. Here's how it works and how to shut it off.

Device Code Phishing Is How Midnight Blizzard Beat MFA on Hotel Wi-Fi on Latest Hacking News | Cyber Security News, Hacking Tools and Penetration Testing Courses.

Welcome back, aspiring cyberwarriors!

Lately, we’ve covered several tools you can use with your laptop to track nearby devices and people. While they’re useful, their effectiveness depends on the strength of your Bluetooth adapter, and, of course, you need to have your laptop with you.

This time, we’re doing things differently. We want to show you a device that can automatically monitor nearby devices for extended periods, anywhere you choose to place it, and as often as you want. It doesn’t rely solely on Bluetooth, as it also uses Wi-Fi, which is far more likely to be enabled, increasing the chances of detecting someone in your area.

What is Paxcounter

Paxcounter is an open-source firmware project that takes a cheap little ESP32 development board and turns it into a sensor that can count people. Almost every smartphone in the world is constantly sending out small Wi-Fi signals, called probe requests, and Bluetooth signals too, even when the phone is not connected to anything. Paxcounter listens for these signals in the air. It counts how many different devices it hears during each scan, and from that, it can tell you a real time estimate of how many people are nearby.

The project started out as a simple way to measure how many passengers or pedestrians pass through a certain spot. But over time, it grew into something much bigger. Now it works as a general purpose IoT platform, built on hardware that usually costs somewhere between $10 and $30. Besides its main job of counting Wi-Fi and Bluetooth devices, a Paxcounter can also read environmental sensors, track its GPS position, keep accurate time, and send all of that data out through LoRaWAN, MQTT, a local serial connection, or straight onto an SD card. 

How the Counting Works

The way Paxcounter counts people is simple, but it was clearly built with privacy in mind from the very start. Every scan cycle, which lasts 60 seconds by default, the device switches its Wi-Fi and Bluetooth radios into scanning mode and listens for probe requests and advertisement packets coming from nearby devices. Each of these packets carries a MAC address. Paxcounter takes just the last two bytes of that address and turns them into a short, temporary ID. This ID is only used to check for duplicates during that one scan cycle. Once the cycle ends, the count of unique IDs gets sent out, and the whole list is wiped from memory. The firmware also does not try to fingerprint any device. It never tries to figure out a phone’s brand, its operating system, or who owns it. All it wants to know is whether that device has already been counted in the current window.

This scan and clear cycle just keeps repeating, either nonstop or on a schedule if deep sleep power saving is turned on. The results, which include the Wi-Fi count, the Bluetooth count, and sometimes live sensor readings too, get packed into a small payload and sent out through whatever channel the device is set up to use. One thing worth knowing is that Wi-Fi and Bluetooth scanning actually share the same 2.4 GHz radio hardware on the ESP32. So running both scans at the same time slightly lowers the accuracy of each one. Because of that, the project’s own advice is to split Wi-Fi only counting and Bluetooth only counting across two separate devices whenever the best possible accuracy is needed for both.

One Firmware, Many Boards

Paxcounter comes with a hardware abstraction layer and its own pin mapping files for dozens of ESP32 and ESP32-S3 boards. These come from well known manufacturers like LILYGO and TTGO, Heltec, Pycom, WeMos, M5Stack, and Adafruit, and there is also a generic template ready for boards that are not officially supported yet. LILYGO even sells a ready-made board called Paxcounter LoRa, built specifically to run this firmware. 

Depending on which board you pick, your device can end up supporting a LoRaWAN radio for sending data over long distances while using very little power, an OLED status screen, or a single color, RGB, or larger LED matrix light to show status. It can also support a physical button for flipping through display pages or sending an alarm message, battery voltage monitoring, GPS positioning, a real time clock chip along with IF482 or DCF77 time telegram output, and even an SD card slot for logging data locally when there is no network around.

Because the whole system was designed to be truly portable, the documentation goes into real detail about power draw, which usually sits somewhere between 450 and 1000 milliwatts depending on how the device is set up. It also makes good use of the ESP32’s deep sleep mode, so a device can keep running for a long stretch of time on just one 18650 lithium ion battery cell. Members of the community have already shared several 3D printable enclosure designs on Thingiverse for the more popular boards.

Getting the Device Up and Running

Paxcounter is built using PlatformIO instead of the plain Arduino IDE. This choice lets it work smoothly with editors like Visual Studio Code, Atom, or Eclipse, and it gives the project reproducible, script driven builds. In fact, the repository runs an automated PlatformIO build check every single time the code changes, using GitHub Actions, and there is even a CodeFactor badge that keeps an eye on ongoing code quality.

The configuration is intentionally spread across a handful of different files instead of being crammed into just one. This keeps board specific settings, behavioral settings, and personal settings nicely separated from each other. The platformio.ini file is where you select which board’s hardware profile you want to compile against. The paxcounter.conf file handles behavioral settings, things like how long a scan cycle lasts, sleep timing, and payload options. The shared lmic_config.h file sets the LoRaWAN region and frequency plan, so it matches the rules where you live. The shared loraconf.h file holds the device’s LoRaWAN join credentials, and the project recommends using OTAA rather than ABP for this. And the shared ota.conf file stores the Wi-Fi credentials the device uses for over the air firmware updates.

You can upload firmware the traditional way, over USB, or once a device has joined a LoRaWAN network, you can push updates over the air instead. A remote command tells the board to connect to Wi-Fi, check a hosted repository called PAX.express for a newer build, and then download and flash it automatically. If anything goes wrong during that process, it will roll back to the previous version on its own. Devices can also be set up to open a small local web based bootstrap menu right when they power on, which lets you upload a firmware file manually, even from a phone in tethering mode, without needing PlatformIO installed on site.

Configuration and Extensibility

Beyond just picking a board, Paxcounter gives you a long list of settings you can tune to fit your needs. It can log environmental data from sensors like the Bosch BMP180, BME280, BMP280, or BME680, read a Nova SDS011 particulate matter sensor to track dust in the air, and keep accurate time using either a DS3231 real time clock or a connected GPS module. 

Display and LED

On boards that come with an OLED display, Paxcounter shows live status information you can cycle through with a short press of the button. This includes the current pax count, meaning the people count, a histogram of recent activity, GPS status, environmental sensor readings, and the time of day. 

A long press of that same button sends an alarm message out over the network instead, which is a simple way to flag a problem from out in the field without needing any other kind of interface. Even on boards that do not have a display at all, a status LED still tells you what the device is doing through its blink pattern. You get a brief flash whenever a new Wi-Fi or Bluetooth device is spotted, a quick blink while the device is joining the LoRaWAN network, a short blink during data transmission, and a slow, long blink if there is a LoRaWAN stack error. Boards that have an RGB LED get a color coded version of these same signals.

How You Receive the Data

Once a Paxcounter has counted the people nearby and packed everything into a message, that data has to go somewhere so you can actually see it. How that happens depends on which output the device is using, and the good news is you can turn on more than one at the same time. If you are using LoRaWAN, which is the most common setup, the device does not send the data straight to you. Instead, a nearby LoRaWAN gateway picks up the signal first and forwards it on to a network server, usually The Things Stack. There is a small decoder script included with the project, and its job is to take that raw message and turn it into numbers you can actually read, something like a pax count of 14. From there, The Things Stack can pass the data along to your own app or dashboard using MQTT or a webhook, or you can simply watch it come in live through the built in console.

If a board does not have LoRa hardware built in, it can just skip the gateway completely and send that same kind of data straight to an MQTT service over Wi-Fi instead. You can also connect the device to a computer using a USB cable and read the numbers directly from a serial connection. This is a simple way to test things out without needing to set up a network at all. If SD card logging is turned on, everything also gets saved locally as a CSV file, so you can pull the card out later and open it up in a spreadsheet. This comes in handy in places where there is no network coverage to rely on. 

Where It’s Used

Because a single Paxcounter device is cheap to build and can be left running unattended for a long time, you will find it popping up in a pretty wide range of places. Retailers and shopping centers use it to measure foot traffic without needing to install cameras. Event organizers use it to watch how crowds move around a venue in real time. Pentesters can get a passive read on how many Wi-Fi and Bluetooth devices are active in a building, or to notice unexpected devices showing up where they shouldn’t, all without needing camera access or network credentials.

Legal and Privacy Considerations

Since Paxcounter’s whole job involves listening to wireless traffic, its documentation is unusually upfront about the legal side of things. It points out that sniffing Wi-Fi and Bluetooth MAC addresses may be regulated or restricted depending on where you live, and it links to specific starting references for the US, the UK, the Netherlands and the EU, and Germany. It also makes clear that the legal responsibility for how a device is built and deployed falls on the person doing it, especially for public deployments where the results might get published somewhere. On the technical side of privacy, the project’s own design actually holds up pretty well against that legal backdrop. Identifiers are only ever built from the last two bytes of a scanned MAC address, they are kept in memory just for the length of one scan cycle, and then they are discarded completely. No MAC addresses or identifiers are ever sent out over the network, and the firmware does not do any extra tracking or fingerprinting of the devices it scans.

Summary

What really makes Paxcounter stand out is not any single feature on its own. It is the whole combination working together. One piece of open source firmware supports dozens of cheap boards, runs for a long time on a small battery, counts people without saving anything identifying about them, doubles as a general environmental sensor node, speaks LoRaWAN, MQTT, serial, and SD card all at once, and can be fully reconfigured from a distance once it is out in the field. The full source code, the complete board list, and all the documentation are available on GitHub.

If you enjoy experimenting with frequencies and trying new things, we recommend signing up for our SDR for Hackers training. With Master OTW, you’ll learn how to use your computer and inexpensive SDR hardware to explore and hack a wide range of radio signals.

The post SDR (Signals Intelligence) for Hackers: Tracking People with ESP32-Paxcounter first appeared on Hackers Arise.