Blocking access to a WiFi network demands a lot of responsibility. If you're the one managing the network, there shouldn't be any issue, and if the idea is just to experiment… all you need is an ESP8266 module, which you must load with the firmware called “ESP8266 Deauther,” developed by Stefan Kremser, also known as “spacehuhn”.
Recently, I came across a couple of articles about bar, café, and restaurant owners tired of customers who walk in and only stare at a screen while connected to the WiFi. Some owners have gone to the extreme of completely removing their wireless networks, obviously offending more than a few “offended” customers, but I later had a question: Is there no temporary way to block access to a WiFi network? While it's possible to hide the SSID so it doesn't appear on mobile devices, someone with the right tools could still find the network. Then there are whitelist and blacklist systems based on MAC addresses, but that's not exactly convenient. The alternative we're going to mention today is… applying a “jammer” to our own network.
What You'll Need
It all starts with one of the very popular ESP8266 modules, which you can get for about three euros (on average) through eBay and other stores. Then you need to visit the official page of the excellent ESP8266 Deauther project, brought to us by Stefan Kremser, known as “spacehuhn” on GitHub. Kremser describes two methods for flashing his firmware, and the simplest boils down to getting the latest version of the .bin file and then flashing it with the nodemcu-flasher tool. This is done directly on Windows, and those who prefer to compile from source can do so with Arduino.
How to Use It
The ESP8266 needs a power source (it can be a smartphone if we have an OTG cable), and once powered on, we connect to its “pwned” network, password “deauther.” The server is at 192.168.4.1. Inside, we search for our SSID and click “deauth” to start the attack. As long as the ESP8266 receives power, no one within range will be able to connect to our WiFi. It was also suggested to me that this could be used as a kind of parental control, disconnecting the little ones when it's time to sleep.
To conclude, Deauther doesn't work on all networks. If the router supports 802.11w or operates at 5 GHz, the ESP8266 can't touch it.
