picocom_skill

Overview

This skill provides a reliable interface to interact with IoT device UART consoles using picocom and a Python serial helper. It is designed for pentesting workflows: device enumeration, bootloader interaction, AT command enumeration, vulnerability discovery, and obtaining interactive shells. The helper script cleans output, detects prompts, handles timeouts, and logs all serial I/O for safe, observable sessions.

How this skill works

The skill wraps picocom with a Python helper that opens the serial device, normalizes and cleans device output (removing echoes, prompts, and ANSI codes), and detects prompts or AT-style responses. It supports single commands, batch scripts, interactive mode, passive monitor mode with triggers, and JSON output for automated parsing. All I/O is logged by default to /tmp/serial_session.log so you can tail the file in another terminal to observe activity in real time.

When to use it

• When you need to enumerate an embedded device (processes, network config, filesystem, firmware versions).
• When interacting with bootloaders (U-Boot) or interrupting boot sequences for exploitation.
• When probing cellular/satellite modems or AT interfaces for sensitive info or misconfigurations.
• When passively capturing boot logs, triggered debug output, or authentication leakages via UART.
• When scripting repeatable serial checks or integrating UART data into automated pentest workflows.

Best practices

• Always include --logfile /tmp/serial_session.log so sessions can be observed with tail -f.
• Prefer the serial_helper.py wrapper over raw picocom for reliable prompt detection and cleaner output.
• Use --prompt to supply a device-specific regex when known to improve command/response pairing.
• For modems and AT devices, use --at-mode to correctly interpret OK/ERROR style responses.
• Run picocom interactions from a background shell or a separate terminal to avoid TTY conflicts.

Example use cases

• Run a one-off command: python3 serial_helper.py --device /dev/ttyUSB0 --command "ifconfig" --logfile /tmp/serial_session.log
• Enumerate modem details with AT batch script to collect IMEI, firmware, and network status.
• Monitor boot sequence: use --monitor with a trigger-script to reboot the device and capture boot logs for secret leaks.
• Interactive shell access to an embedded device to inspect /etc, services, and running processes.
• Passive monitoring during authentication brute-force to see if credentials or tokens are printed to UART.