While hackers know and love the Raspberry Pi, many don't know of its cheaper cousin, the microcontroller. Unlike a Pi, which can be used more or less like a regular computer, microcontrollers like the Wi-Fi connected ESP8266 require some necessary programming skill to master. In this guide, we'll build an Arduino program from scratch and explain the code structure in a way anyone can understand.
The price of hacking Wi-Fi has fallen dramatically, and low-cost microcontrollers are increasingly being turned into cheap yet powerful hacking tools. One of the most popular is the ESP8266, an Arduino-programmable chip on which the Wi-Fi Deauther project is based. On this inexpensive board, a hacker can create fake networks, clone real ones, or disable all Wi-Fi in an area from a slick web interface.
If you want to get started sniffing Wi-Fi networks, you usually need to start with a wireless network adapter. But thanks to a Wi-Fi sniffing library written in Arduino and the ultra-cheap ESP8266 chip, you might not need one. For less than $10 in electronics, you can build a tiny Arduino Wi-Fi sniffer that saves Wireshark-compatible PCAP files and fits anywhere.
A relay is an electrical component that works like a light switch, where it's turned on or off with an electrical signal. By connecting a relay to a Wi-Fi connected microcontroller like an ESP8266, you can build a connected switch that can be controlled from the web browser of any device connected to the same Wi-Fi network — all for just a couple of dollars.
Smartphones and other Wi-Fi enabled devices send radio signals called probe frames to locate nearby wireless networks, which makes them easy to track by listening for their unique MAC address. To show how this kind of tracking works, we can program a NodeMCU in Arduino to sniff the air for packets from any device we want to track, turning on an LED when it's detected nearby.
The most common Wi-Fi jamming attacks leverage deauthentication and disassociation packets to attack networks. This allows a low-cost ESP8266-based device programmed in Arduino to detect and classify Wi-Fi denial-of-service attacks by lighting a different color LED for each type of packet. The pattern of these colors can also allow us to fingerprint the tool being used to attack the network.
Smartphones and laptops are constantly sending Wi-Fi radio signals, and many of these signals can be used to track us. In this guide, we'll program a cheap IoT device in Arduino to create hundreds of fake networks with common names; This will cause nearby devices to reveal their real trackable MAC address, and it can even let an attacker take over the phone's data connection with no warning.
Hackers and makers are often grouped under the same label. While hackers draw on computer science skills to write programs and find bugs, makers use electrical engineering to create hardware prototypes from microprocessor boards like the Arduino. We'll exercise both sets of skills to program a $6 NodeMCU to display the status of a Wi-Fi link via an LED, allowing us to monitor for jamming attacks.
Arduino is a language that's easy to learn and supported on many incredibly low-cost devices, two of which are the $2 Digispark and a $3 ESP8266-based board. We can program these devices in Arduino to hijack the Wi-Fi data connection of any unlocked macOS computer in seconds, and we can even have it send data from the target device to our low-cost evil access point.
Individually addressable LEDs, also commonly called "NeoPixels" after the popular Adafruit product, are a bright and colorful way to get started with basic Python programming. With an inexpensive ESP8266 or ESP32 microcontroller, it's easy to get started programming your own holiday lighting animations on a string of NeoPixels with beginner-friendly MicroPython!
For anyone interested in using cheap, Wi-Fi-connected microcontrollers like the ESP8266, the Arduino programming language can be a barrier to entry. Based on C++, Arduino requires knowledge of more computer science than languages like Python. Fortunately for beginners, setting up MicroPython on an ESP8266 allows anyone to write Python on affordable microcontrollers in a matter of minutes.
The $35 Raspberry Pi is an amazingly useful single-board computer (SBC) with a good balance of price, performance, and connectivity options. But for some projects, it just isn't enough. Whether you need more computing power, a smaller size, or better machine-learning capabilities, there are other options available.
Fireworks are the best part about the Fourth of July and other celebrations, but they can easily cause accidental injuries. It's both safer and more fun to set them off remotely, so we'll hack some standard fireworks with nichrome wire, a relay, and an Arduino to ignite remotely over Wi-Fi using any smartphone or computer.