Inspired By
Chasing Your Tail
Open-source Raspberry Pi WiFi probe request analyzer
Shadow Prox was directly inspired by "Chasing Your Tail", an open-source project that monitors WiFi probe requests using a Raspberry Pi and Kismet to detect if wireless devices are following you.
The original concept was simple but powerful: your phone constantly broadcasts probe requests looking for known WiFi networks. By capturing these probes, you can detect if the same device appears near you across different times and locations — a potential indicator of surveillance.
From WiFi to Bluetooth
Shadow Prox takes this concept and evolves it from WiFi probe requests to Bluetooth Low Energy (BLE) — a far more pervasive radio protocol. Every AirTag, SmartTag, Tile tracker, smartwatch, wireless earbud, and even modern car key fob broadcasts BLE advertisements. By monitoring BLE instead of WiFi, Shadow Prox detects a much wider range of potential tracking devices, including purpose-built stalking tools like hidden AirTags.
How Shadow Prox Builds on the Original
| Chasing Your Tail | Shadow Prox | |
|---|---|---|
| Radio | WiFi 2.4/5 GHz probe requests | Bluetooth Low Energy (BLE) + WiFi (via ESP32) |
| Hardware | Raspberry Pi + WiFi adapter + Kismet | iPhone, Mac, or ESP32-S3 custom device |
| Portability | Stationary setup | Pocket-sized — runs on your phone |
| Detection | SSID probe list matching | Multi-field fingerprinting, GATT probing, device tagging, MAC rotation tracking |
| Tracking | Time windows (5/10/15/20 min) | GPS location correlation, multi-location persistence scoring, behavioral analysis |
| Threats | Device reappearance alerts | 5 threat detectors: known trackers, hidden trackers, clones, MITM, relay attacks |
| Visualization | Terminal logs, KML export | 3D globe map with animated zoom, real-time device list, threat badges |
Acknowledgments
Open Source Community
Shadow Prox builds on the work of many open-source projects and databases:
- Nordic Semiconductor bluetooth-numbers-database — 4,000+ company IDs, 125 service UUIDs, 664 characteristic UUIDs, 342 appearance values, 227 Apple device models
- Bluetooth SIG Assigned Numbers — Official registry of member service UUIDs and company identifiers
- Kismet — Wireless network detector and sniffer that powered the original Chasing Your Tail
- ESP-IDF & NimBLE — Espressif's IoT Development Framework and the NimBLE BLE stack
The Problem We're Solving
Bluetooth surveillance is a growing concern. AirTags and similar devices have been documented in stalking cases worldwide. While Apple and Google have added some built-in detection, their solutions only catch their own products and can take hours to alert. Shadow Prox detects all BLE devices — from any manufacturer — in real time.
Built with AI Assistance
Shadow Prox is developed with the help of Claude Code (Anthropic) as an AI pair programming partner, accelerating development across Swift, Python, C (ESP-IDF), Django, and web technologies simultaneously.