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# Espilon # Espilon
**Espilon** is an embedded agent framework for ESP32 microcontrollers, designed for network surveillance, reconnaissance, and distributed communication in constrained IoT environments. Developed in C with **ESP-IDF**, Espilon demonstrates how to build lightweight, efficient implants capable of communicating via Wi-Fi or GPRS. **Embedded ESP32 Agent Framework for Security Research and IoT**
[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE) [![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE)
[![ESP-IDF](https://img.shields.io/badge/ESP--IDF-v5.3.2-green.svg)](https://github.com/espressif/esp-idf) [![ESP-IDF](https://img.shields.io/badge/ESP--IDF-v5.3.2-green.svg)](https://github.com/espressif/esp-idf)
[![Platform](https://img.shields.io/badge/Platform-ESP32-red.svg)](https://www.espressif.com/en/products/socs/esp32) [![Platform](https://img.shields.io/badge/Platform-ESP32-red.svg)](https://www.espressif.com/en/products/socs/esp32)
> **IMPORTANT:** This is a security research and educational tool. It must only be used in authorized penetration testing, controlled environments, CTF competitions, or educational contexts. Unauthorized use against systems you don't own or have explicit permission to test is illegal. > **IMPORTANT**: Espilon is intended for security research, authorized penetration testing, and education. Unauthorized use is illegal. Always obtain written permission before any deployment.
--- ---
## Table of Contents ## Full Documentation
- [Overview](#overview) **[View the full documentation here](https://docs.espilon.net)**
- [Features](#features)
- [Architecture](#architecture) The MkDocs documentation includes:
- [Getting Started](#getting-started)
- [Modules](#modules) - Step-by-step installation guide
- [C2 Server](#c2-server) - WiFi and GPRS configuration
- [Configuration](#configuration) - Module and command reference
- [Hardware Requirements](#hardware-requirements) - Multi-device flasher guide
- [Security](#security) - C2 protocol specification
- [Documentation](#documentation) - Examples and use cases
- [Roadmap](#roadmap)
- [Contributing](#contributing)
- [Authors](#authors)
- [License](#license)
--- ---
## Overview ## Quick Start
Initially presented as a PoC at **Le Hack (June 2025)**, Espilon has evolved into a **modular codebase** that enables: ### Prerequisites
- Understanding embedded agent construction - ESP-IDF v5.3.2
- Manipulating ESP32's low-level network stack - Python 3.8+
- Developing specialized modules (sniffer, proxy, reconnaissance, vision) - ESP32 (any compatible model)
- Studying IoT communication scenarios in cybersecurity research contexts - LilyGO T-Call for GPRS mode (optional)
The framework is **compatible with all ESP32 variants** supported by ESP-IDF and offers two network modes: ### Quick Installation
- **Wi-Fi** (802.11 b/g/n) ```bash
- **GPRS** (SIM800/808 modules) # 1. Install ESP-IDF v5.3.2
mkdir -p ~/esp
cd ~/esp
git clone -b v5.3.2 --recursive https://github.com/espressif/esp-idf.git
cd esp-idf
./install.sh esp32
. ./export.sh
# 2. Clone Espilon
cd ~
git clone https://github.com/yourusername/epsilon.git
cd epsilon/espilon_bot
# 3. Configure
idf.py menuconfig
# 4. Build and flash
idf.py build
idf.py -p /dev/ttyUSB0 flash monitor
```
**Minimal configuration** (menuconfig):
```
Espilon Bot Configuration
|- Device ID: "your_unique_id"
|- Network -> WiFi
| |- SSID: "YourWiFi"
| |- Password: "YourPassword"
|- Server
|- IP: "192.168.1.100"
|- Port: 2626
```
--- ---
## Features ## What is Espilon?
### Core Capabilities Espilon transforms affordable ESP32 microcontrollers (~$5) into powerful networked agents for:
- **Dual Network Backend**: WiFi or GPRS connectivity - **Security research**: WiFi testing, network reconnaissance, IoT pentesting
- **Encrypted C2 Communication**: ChaCha20 encryption with Protocol Buffers serialization - **Education**: Learning embedded systems, network protocols, FreeRTOS
- **Modular Architecture**: Enable/disable components at compile time - **IoT prototyping**: Distributed communication, monitoring, sensors
- **Async Command Execution**: FreeRTOS-based task management
- **Auto-reconnection**: Persistent TCP connection with automatic recovery
- **Multi-device Support**: Centralized C2 can manage multiple agents simultaneously
### Network Tools ### Connectivity Modes
- **ARP Scanner**: Local network discovery | Mode | Hardware | Range | Use Case |
- **Custom ICMP Ping**: Network reachability testing |------|----------|-------|----------|
- **TCP Reverse Proxy**: Traffic forwarding and tunneling | **WiFi** | Standard ESP32 | 50-100m | Labs, buildings |
- **802.11 Packet Sniffer**: Monitor mode packet capture | **GPRS** | LilyGO T-Call | National (2G) | Mobile, remote |
- **Network Traffic Generation**: Controlled testing scenarios
### Wireless Manipulation
- **Fake Access Point**: Rogue AP with WPA2 support
- **Captive Portal**: DNS hijacking with customizable landing page
- **AP+STA Concurrent Mode**: NAPT routing implementation
- **Client Session Tracking**: Monitor connected devices
### Reconnaissance
- **ESP32-CAM Support**: Image capture and UDP streaming
- **BLE Trilateration**: Position estimation using RSSI (WIP)
- **Network Discovery**: Automated reconnaissance capabilities
--- ---
## Architecture ## Architecture
Espilon is built on a **unified core** with an **ESP-IDF component system** activated at compile time.
``` ```
┌─────────────────────────────────────────────────┐ +---------------------------------------------------------+
│ ESP32 Agent │ | ESP32 Agent |
├─────────────────────────────────────────────────┤ | +-----------+ +----------+ +---------------------+ |
│ Modules: Network | FakeAP | Recon | System │ | | WiFi/ |->| ChaCha20 |->| C2 Protocol | |
├─────────────────────────────────────────────────┤ | | GPRS |<-| Crypto |<-| (nanoPB/TCP) | |
│ Command Registry & Dispatcher │ | +-----------+ +----------+ +---------------------+ |
├─────────────────────────────────────────────────┤ | | | | |
│ Core: WiFi/GPRS | Crypto | Protobuf | COM │ | +-----------------------------------------------------+|
├─────────────────────────────────────────────────┤ | | Module System (FreeRTOS) ||
│ LWIP Stack | FreeRTOS | ESP-IDF │ | | [Network] [FakeAP] [Recon] [Custom...] ||
└─────────────────────────────────────────────────┘ | +-----------------------------------------------------+|
+---------------------------------------------------------+
TCP (encrypted) | Encrypted TCP
+---------------------+
┌─────────────────────────────────────────────────┐ | C2 Server (C3PO) |
│ C2 Server (Python) │ | - Device Registry |
├─────────────────────────────────────────────────┤ | - Group Management |
│ CLI | Device Registry | Group Management │ | - CLI Interface |
├─────────────────────────────────────────────────┤ +---------------------+
│ Transport | Crypto | Protobuf | Commands │
└─────────────────────────────────────────────────┘
``` ```
### Core Components ### Key Components
The core provides: - **Core**: Network connection, ChaCha20 crypto, nanoPB protocol
- **Modules**: Extensible system (Network, FakeAP, Recon, etc.)
- **Network Backend**: WiFi or GPRS (configured via `menuconfig`) - **C2 (C3PO)**: Python asyncio server for multi-agent control
- **Persistent TCP/IP**: Connection management with auto-reconnection - **Flasher**: Automated multi-device flashing tool
- **Encryption**: ChaCha20 stream cipher
- **Serialization**: nanoPB (Protocol Buffers for embedded systems)
- **Command Parser**: Dispatches commands to registered handlers
- **FreeRTOS Tasks**: Dedicated tasks for connection, processing, and crypto
- **State Management**: Connection state tracking and recovery
See [ARCHITECTURE.md](docs/ARCHITECTURE.md) for detailed information.
--- ---
## Getting Started ## Available Modules
### Prerequisites > **Important note**: Modules are **mutually exclusive**. You must choose **only one module** during configuration via menuconfig.
- **ESP-IDF v5.3.2** (or compatible version) ### System Module (Built-in, always active)
- Python 3.8+ (for C2 server and tools)
- ESP32 development board
- USB-to-Serial adapter (if not integrated)
### Quick Start Basic system commands:
1. **Clone the repository** - `system_reboot`: Reboot the ESP32
- `system_mem`: Display memory usage (heap free, heap min, internal free)
```bash - `system_uptime`: Uptime since boot
git clone https://github.com/yourusername/epsilon.git
cd epsilon
```
2. **Set up ESP-IDF environment**
```bash
. $HOME/esp-idf/export.sh
```
3. **Configure the firmware**
```bash
cd espilon_bot
idf.py menuconfig
```
Navigate to `Espilon Configuration` and set:
- Network backend (WiFi/GPRS)
- C2 server IP and port
- Crypto keys (**CHANGE DEFAULT KEYS**)
- Module selection
4. **Build and flash**
```bash
idf.py build
idf.py -p /dev/ttyUSB0 flash
idf.py monitor
```
5. **Start the C2 server**
```bash
cd tools/c2
python3 c3po.py --port 2626
```
For detailed installation instructions, see [INSTALL.md](docs/INSTALL.md).
---
## Modules
Espilon uses a modular architecture where each module is an isolated ESP-IDF component.
### System Module
Basic device management:
- `system_reboot` - Reboot the device
- `system_mem` - Memory usage statistics
- `system_uptime` - Device uptime
### Network Module ### Network Module
Advanced network capabilities: Module for network reconnaissance and testing:
- `ping` - ICMP ping with custom parameters
- `arp_scan` - Discover devices on local network - `ping <host> [args...]`: ICMP connectivity test
- `proxy_start/stop` - TCP reverse proxy - `arp_scan`: Discover hosts on local network via ARP
- `dos_tcp` - Controlled traffic generation (testing only) - `proxy_start <ip> <port>`: Start a TCP proxy
- `proxy_stop`: Stop the running proxy
- `dos_tcp <ip> <port> <count>`: TCP load test (authorized use only)
### FakeAP Module ### FakeAP Module
Wireless manipulation (authorized testing only): Module for creating simulated WiFi access points:
- `fakeap_start` - Create rogue access point
- `portal_start` - Launch captive portal with DNS hijacking - `fakeap_start <ssid> [open|wpa2] [password]`: Start a fake access point
- `sniffer_start` - 802.11 packet capture - `fakeap_stop`: Stop the fake AP
- `fakeap_stop` - Cleanup and restore - `fakeap_status`: Display status (AP, portal, sniffer, clients)
- `fakeap_clients`: List connected clients
- `fakeap_portal_start`: Enable captive portal
- `fakeap_portal_stop`: Disable captive portal
- `fakeap_sniffer_on`: Enable network traffic capture
- `fakeap_sniffer_off`: Disable capture
### Recon Module ### Recon Module
Reconnaissance capabilities: Reconnaissance and data collection module. Two modes available:
- `capture` - ESP32-CAM snapshot (JPEG)
- `stream_start/stop` - UDP video streaming
- `trilat_scan` - BLE device discovery (WIP)
See [MODULES.md](docs/MODULES.md) for complete API documentation. #### Camera Mode (ESP32-CAM)
- `cam_start <ip> <port>`: Start UDP video streaming (~7 FPS, QQVGA)
- `cam_stop`: Stop streaming
#### BLE Trilateration Mode
- `trilat start <mac> <url> <bearer>`: Start BLE trilateration with HTTP POST
- `trilat stop`: Stop trilateration
--- ---
## 🎮 C2 Server **Configuration**: `idf.py menuconfig` -> Espilon Bot Configuration -> Modules
Espilon includes a custom C2 server (`c3po`) specifically designed for ESP32 constraints. Choose **only one module**:
### Features - `CONFIG_MODULE_NETWORK`: Enable the Network Module
- `CONFIG_MODULE_FAKEAP`: Enable the FakeAP Module
- `CONFIG_MODULE_RECON`: Enable the Recon Module
- Then choose: `Camera` or `BLE Trilateration`
- **Device Registry**: Track connected agents by unique ID ---
- **Group Management**: Organize devices into logical groups
- **Command Targeting**: Send commands to individuals, groups, or all
- **Interactive CLI**: Tab completion and help system
- **Encrypted Protocol**: ChaCha20 + Protocol Buffers
- **Plugin System**: Extensible command architecture
### Usage ## Tools
### Multi-Device Flasher
Automated flasher to configure multiple ESP32s:
```bash ```bash
# Start server cd tools/flasher
python3 tools/c2/c3po.py --port 2626 python3 flash.py --config devices.json
# List connected devices
c3po> list
# Send command to device
c3po> send ce4f626b system_mem
# Send to all devices
c3po> send all system_uptime
# Create group
c3po> group add lab ce4f626b a91dd021
# Send to group
c3po> send group lab system_reboot
``` ```
See [tools/c2/README.md](tools/c2/README.md) for detailed C2 documentation. **devices.json**:
--- ```json
{
## Configuration "project": "/path/to/espilon_bot",
"devices": [
Configuration is done via ESP-IDF's `menuconfig` system. {
"device_id": "esp001",
### Key Settings "port": "/dev/ttyUSB0",
"network_mode": "wifi",
``` "wifi_ssid": "MyNetwork",
Espilon Configuration "wifi_pass": "MyPassword",
├── Device ID # Unique identifier (CRC32) "srv_ip": "192.168.1.100"
├── Network Backend Selection }
│ ├── WiFi # SSID, password, STA/AP modes ]
│ └── GPRS # APN, SIM800 config }
├── C2 Server
│ ├── IP Address # Server IP
│ └── Port # Server port (default: 2626)
├── Cryptography
│ ├── ChaCha20 Key # 32-byte encryption key
│ └── Nonce # 12-byte nonce
└── Modules
├── Enable Network Module
├── Enable FakeAP Module
└── Enable Recon Module
├── Camera Mode
└── BLE Trilateration
``` ```
### Security Configuration See [tools/flasher/README.md](tools/flasher/README.md) for complete documentation.
**CRITICAL**: Change default crypto keys before deployment! ### C2 Server (C3PO)
Default keys are for testing only: Command & Control server:
- Default Key: `testde32chars0000000000000000000`
- Default Nonce: `noncenonceno`
Generate secure keys:
```bash ```bash
# Generate 32-byte key cd tools/c2
openssl rand -hex 32 pip3 install -r requirements.txt
python3 c3po.py --port 2626
# Generate 12-byte nonce
openssl rand -hex 12
``` ```
See [SECURITY.md](docs/SECURITY.md) for security best practices. **Commands**:
--- - `list`: List connected agents
- `select <id>`: Select an agent
## Hardware Requirements - `cmd <command>`: Execute a command
- `group`: Manage agent groups
### Minimum Requirements
- **ESP32** (any variant)
- **Flash**: 4MB minimum
- **WiFi**: Integrated 802.11 b/g/n
### For Camera Module
- **ESP32-CAM** (AI-Thinker or compatible)
- **PSRAM**: Required for image buffering
- **Camera**: OV2640 or compatible
### For GPRS Mode
- **ESP32 DevKit** (any variant)
- **SIM800/SIM808** module
- **UART**: GPIO 26 (RX), 27 (TX)
- **Power Management**: GPIOs 4, 23, 5
See [HARDWARE.md](docs/HARDWARE.md) for detailed pinouts and wiring diagrams.
--- ---
## Security ## Security
### Encryption
- **ChaCha20** for C2 communications
- **Configurable keys** via menuconfig
- **Protocol Buffers (nanoPB)** for serialization
**CHANGE DEFAULT KEYS** for production use:
```bash
# Generate random keys
openssl rand -hex 32 # ChaCha20 key (32 bytes)
openssl rand -hex 12 # Nonce (12 bytes)
```
### Responsible Use ### Responsible Use
This tool is designed for: Espilon should only be used for:
- Authorized penetration testing
- Controlled security research
- Educational purposes
- CTF competitions
- IoT security assessments (with permission)
**NEVER** use for: - **Authorized** penetration testing
- Unauthorized network access - **Ethical** security research
- Malicious attacks - Education and training
- Privacy violations - Legitimate IoT prototyping
- Illegal activities
### Security Considerations **Prohibited**: Unauthorized access, malicious attacks, privacy violations.
**Current Implementation:**
- ChaCha20 stream cipher (256-bit key)
- Protocol Buffers serialization
- Implicit authentication via encryption
**Known Limitations:**
- Static nonce (should be unique per message)
- No authenticated encryption (no MAC/Poly1305)
- Hardcoded default credentials
- No forward secrecy
- No device enrollment/revocation
**Recommendations:**
- Use ChaCha20-Poly1305 AEAD
- Implement unique nonce per message
- Add device certificate system
- Use TLS/DTLS for transport security
See [SECURITY.md](docs/SECURITY.md) for complete security documentation.
--- ---
## Documentation ## Use Cases
- [Installation Guide](docs/INSTALL.md) - Detailed setup instructions ### WiFi Pentesting
- [Architecture Overview](docs/ARCHITECTURE.md) - System design and components
- [Module API](docs/MODULES.md) - Complete module documentation - Network security auditing
- [Protocol Specification](docs/PROTOCOL.md) - C2 communication protocol - WPA2/WPA3 robustness testing
- [Hardware Guide](docs/HARDWARE.md) - Pinouts and wiring diagrams - Network mapping
- [Security Best Practices](docs/SECURITY.md) - Security guidelines
- [Development Guide](docs/DEVELOPMENT.md) - Creating custom modules ### IoT Security Research
- [Troubleshooting](docs/TROUBLESHOOTING.md) - Common issues and solutions
- IoT device testing
- Protocol analysis
- Vulnerability detection
### Education
- Cybersecurity labs
- Embedded systems courses
- CTF competitions
--- ---
## Roadmap ## Roadmap
### Short-term ### V2.0 (In Progress)
- [ ] Complete GPRS RX implementation - [ ] Mesh networking (BLE/WiFi)
- [ ] BLE trilateration module completion - [ ] Improve documentation
- [ ] SOCKS5 proxy support - [ ] OTA updates
- [ ] Enhanced multi-flasher tool
- [ ] Persistent C2 storage (groups, history)
- [ ] Request/response correlation tracking
### Long-term
#### Mesh IoT Network
- [ ] Bot-to-bot communication
- [ ] Distributed routing protocols
- [ ] OTA firmware updates
- [ ] Extended range via relay
- [ ] Collaborative multilateration - [ ] Collaborative multilateration
- [ ] Zero-trust mesh architecture
#### Custom PCB
- [ ] Portable design with battery management
- [ ] Integrated antennas (WiFi, GPRS, BLE)
- [ ] Embedded sensors (temperature, motion, etc.)
- [ ] File system storage (SD card)
- [ ] MPU/MCU architecture
- [ ] Blue team & Red team variants
#### Code Improvements
- [ ] Memory optimization - [ ] Memory optimization
- [ ] Module standardization
- [ ] Enhanced C2 protocols
- [ ] Unit testing framework
- [ ] CI/CD pipeline
- [ ] Docker development environment
--- ### Future
## Contributing - [ ] Custom Espilon PCB
- [ ] ESP32-S3/C3 support
Contributions are welcome! This project is now open source to benefit the security research and IoT communities. - [ ] Module SDK for third-party extensions
- [ ] Web UI for C2
### How to Contribute
1. Fork the repository
2. Create a feature branch (`git checkout -b feature/amazing-feature`)
3. Commit your changes (`git commit -m 'Add amazing feature'`)
4. Push to the branch (`git push origin feature/amazing-feature`)
5. Open a Pull Request
### Guidelines
- Follow the existing code style
- Add tests for new features
- Update documentation
- Ensure security best practices
- Only submit authorized security research
See [CONTRIBUTING.md](CONTRIBUTING.md) for detailed guidelines.
---
## Authors
- **@Eun0us** - Main developer, firmware architecture
- **@off-path** - C2 development lead
- **@itsoktocryyy** - Contributor
- **@wepfen** - Contributor
--- ---
## License ## License
[To be determined - Please add appropriate license] Espilon is licensed under **MIT** with a security addendum.
**Recommended licenses for security tools:** See [LICENSE](LICENSE) for full details.
- **MIT License** - Permissive, allows commercial use
- **Apache 2.0** - Permissive with patent protection **In summary**:
- **GPL v3** - Copyleft, modifications must be open source - Free use for research, education, development
- Modification and distribution allowed
- **Obtain authorization** before any deployment
- Malicious use strictly prohibited
--- ---
## Acknowledgments ## Contributors
- ESP-IDF team at Espressif - **@Eun0us** - Core architecture, modules
- Le Hack conference for initial presentation - **@off-path** - C2 server, protocol
- Security research community - **@itsoktocryyy** - Network features, work on Mod Wall Hack
- All contributors and testers - **@wepfen** - Documentation, tools
### Contributing
Contributions welcome! See [CONTRIBUTING.md](CONTRIBUTING.md).
**Join us**:
- Report bugs
- Propose features
- Submit PRs
- Improve documentation
--- ---
## Contact ## Useful Links
- GitHub Issues: [Report bugs or request features](https://github.com/yourusername/epsilon/issues) - **[Full documentation](https://docs.espilon.net)**
- Discussions: [Community discussions](https://github.com/yourusername/epsilon/discussions) - **[ESP-IDF Documentation](https://docs.espressif.com/projects/esp-idf/)**
- **[LilyGO T-Call](https://github.com/Xinyuan-LilyGO/LilyGO-T-Call-SIM800)**
- **French README**: [README.md](README.md)
--- ---
**Legal Disclaimer**: This tool is provided for educational and authorized testing purposes only. Users are solely responsible for ensuring their use complies with applicable laws and regulations. The authors assume no liability for misuse or damage caused by this software. ## Support
- **Issues**: [GitHub Issues](https://github.com/Espilon-Net/Espilon-Source/issues)
- **Discussions**: [GitHub Discussions](https://github.com/Espilon-Net/Espilon-Source/discussions)
---
**Originally presented at Le Hack (June 2025)**
**Made with love for security research and education**

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## Documentation Complète ## Documentation Complète
**[Consultez la documentation complète ici](https://github.com/yourusername/espilon-docs)** **[Consultez la documentation complète ici](https://docs.espilon.net)**
La documentation MkDocs inclut : La documentation MkDocs inclut :
@ -290,13 +290,13 @@ Espilon doit être utilisé uniquement pour :
### V2.0 (En cours) ### V2.0 (En cours)
- [ ] Mesh networking (BLE/WiFi) - [ ] Mesh networking (BLE/WiFi)
- [ ] Améliorer la Documentations
- [ ] OTA updates - [ ] OTA updates
- [ ] Multilatération collaborative - [ ] Multilatération collaborative
- [ ] Optimisation mémoire - [ ] Optimisation mémoire
### Future ### Future
- [ ] Améliorer la Documentations **(en cours)**
- [ ] PCB custom Espilon - [ ] PCB custom Espilon
- [ ] Support ESP32-S3/C3 - [ ] Support ESP32-S3/C3
- [ ] Module SDK pour extensions tierces - [ ] Module SDK pour extensions tierces
@ -311,6 +311,7 @@ Espilon est sous licence **MIT** avec addendum de sécurité.
Voir [LICENSE](LICENSE) pour les détails complets. Voir [LICENSE](LICENSE) pour les détails complets.
**En résumé** : **En résumé** :
- Utilisation libre pour recherche, éducation, développement - Utilisation libre pour recherche, éducation, développement
- Modification et distribution autorisées - Modification et distribution autorisées
- **Obtenir autorisation** avant tout déploiement - **Obtenir autorisation** avant tout déploiement
@ -340,7 +341,7 @@ Contributions bienvenues ! Voir [CONTRIBUTING.md](CONTRIBUTING.md).
## Liens Utiles ## Liens Utiles
- **[Documentation complète](https://github.com/Espilon-Net/espilon-docs)** - **[Documentation complète](https://docs.espilon.net)**
- **[ESP-IDF Documentation](https://docs.espressif.com/projects/esp-idf/)** - **[ESP-IDF Documentation](https://docs.espressif.com/projects/esp-idf/)**
- **[LilyGO T-Call](https://github.com/Xinyuan-LilyGO/LilyGO-T-Call-SIM800)** - **[LilyGO T-Call](https://github.com/Xinyuan-LilyGO/LilyGO-T-Call-SIM800)**
- **English README** : [README.en.md](README.en.md) - **English README** : [README.en.md](README.en.md)