/picocom

name: picocom
description: Use picocom to interact with IoT device UART consoles for pentesting operations including device enumeration, vulnerability discovery, bootloader manipulation, and gaining root shells. Use when the user needs to interact with embedded devices, IoT hardware, or serial consoles.

IoT UART Console (picocom)

This skill enables interaction with IoT device UART consoles using picocom for security testing and penetration testing operations. It supports bootloader interaction, shell access (with or without authentication), device enumeration, and vulnerability discovery.

Prerequisites

• picocom must be installed on the system
• Python 3 with pyserial library (`sudo pacman -S python-pyserial` on Arch, or `pip install pyserial`)
• UART connection to the target device (USB-to-serial adapter, FTDI cable, etc.)
• Appropriate permissions to access serial devices (typically /dev/ttyUSB* or /dev/ttyACM*)

Recommended Approach: Serial Helper Script

**IMPORTANT**: This skill includes a Python helper script (`serial_helper.py`) that provides a clean, reliable interface for serial communication. **This is the RECOMMENDED method** for interacting with IoT devices.

Default Session Logging

**ALL commands run by Claude will be logged to `/tmp/serial_session.log` by default.**

To observe what Claude is doing in real-time:

# In a separate terminal, run:
tail -f /tmp/serial_session.log

This allows you to watch all serial I/O as it happens without interfering with the connection.

Why Use the Serial Helper?

The helper script solves many problems with direct picocom usage:

• **Clean output**: Automatically removes command echoes, prompts, and ANSI codes
• **Prompt detection**: Automatically detects and waits for device prompts
• **Timeout handling**: Proper timeout management with no arbitrary sleeps
• **Easy scripting**: Simple command-line interface for single commands or batch operations
• **Session logging**: All I/O logged to `/tmp/serial_session.log` for observation
• **Reliable**: No issues with TTY requirements or background processes

Quick Start with Serial Helper

**Single Command:**

python3 .claude/skills/picocom/serial_helper.py --device /dev/ttyUSB0 --command "help"

**With Custom Prompt (recommended for known devices):**

python3 .claude/skills/picocom/serial_helper.py --device /dev/ttyUSB0 --prompt "User@[^>]+>" --command "ifconfig"

**Interactive Mode:**

python3 .claude/skills/picocom/serial_helper.py --device /dev/ttyUSB0 --interactive

**Batch Commands from File:**

# Create a file with commands (one per line)
echo -e "help\ndate\nifconfig\nps" > commands.txt
python3 .claude/skills/picocom/serial_helper.py --device /dev/ttyUSB0 --script commands.txt

**JSON Output (for parsing):**

python3 .claude/skills/picocom/serial_helper.py --device /dev/ttyUSB0 --command "help" --json

**Debug Mode:**

python3 .claude/skills/picocom/serial_helper.py --device /dev/ttyUSB0 --command "help" --debug

**Session Logging (for observation):**

# Terminal 1 - Run with logging
python3 .claude/skills/picocom/serial_helper.py \
  --device /dev/ttyUSB0 \
  --prompt "User@[^>]+>" \
  --logfile /tmp/session.log \
  --interactive

# Terminal 2 - Watch the session in real-time
tail -f /tmp/session.log

**Note:** See `OBSERVING_SESSIONS.md` for comprehensive guide on monitoring serial sessions.

See [examples.md](examples.md) for full worked attack walkthroughs: basic connection/enumeration, U-Boot bootloader exploitation, login-auth bypass, privilege escalation from a limited user, and firmware extraction.

Monitor Mode (Passive Listening)

**NEW FEATURE**: Monitor mode is designed for passive UART monitoring where the device outputs logs without prompts or interaction.

**Use cases:**

• Monitoring boot logs from devices without interactive consoles
• Capturing triggered output when external actions are performed
• Testing if network requests or hardware events generate UART logs
• Baseline vs triggered output comparison

**Basic passive monitoring:**

python3 .claude/skills/picocom/serial_helper.py \
  --device /dev/ttyUSB0 \
  --monitor \
  --duration 30 \
  --logfile /tmp/uart.log

**Monitor with external trigger script:**

# Run external script after 5 seconds and capture triggered UART output
python3 .claude/skills/picocom/serial_helper.py \
  --device /dev/ttyUSB0 \
  --monitor \
  --duration 60 \
  --trigger-script "python3 /path/to/test_script.py" \
  --trigger-delay 5 \
  --logfile /tmp/triggered_uart.log

**Monitor with baseline capture:**

# Capture 10s baseline, run trigger at 15s, continue for total 60s
python3 .claude/skills/picocom/serial_helper.py \
  --device /dev/ttyUSB0 \
  --monitor \
  --duration 60 \
  --trigger-script "curl http://192.168.1.100/api/reboot" \
  --trigger-delay 15 \
  --baseline-duration 10 \
  --logfile /tmp/reboot_monitor.log

**Monitor mode options:**

• `--duration SECONDS` - Total monitoring time (default: 30)
• `--trigger-script CMD` - External command/script to run during monitoring
• `--trigger-delay SECONDS` - When to run trigger (default: 5)
• `--baseline-duration SECONDS` - Capture baseline before trigger (default: 0)
• `--logfile FILE` - Log all I/O to file
• `--json` - Output results in JSON format

**Output includes:**

• Real-time timestamped console output
• Baseline vs trigger vs post-trigger categorization
• Trigger script exit code and output
• Summary statistics (bytes captured in each phase)
• Timeline with all captured data

Serial Helper Options

Required (one of):
  --command, -c CMD         Execute single command
  --interactive, -i         Enter interactive mode
  --script, -s FILE         Execute commands from file
  --monitor, -m             Passive monitoring mode (just listen, no commands)

Connection Options:
  --device, -d DEV          Serial device (default: /d