anthrax3 / lonely-shell

minimal https reverse shell

lonely-shell

This is a proof of concept, minimal Windows reverse shell written in Golang that uses HTTPS/TLS for communication. The Linux server uses a self-signed certificate and hosts a single static file that contains a Windows command. The Windows client is a 64-bit portable executable that does a GET request every 30 seconds to obtain a Windows command from the server which then is executed and the results are sent via POST. A traffic file is included with this repository to show an example of the encrypted reverse shell communication. Also, a simple python script is provided to easily change the Windows command that the reverse shell will execute.

This project was created due to the lack of open-source Windows reverse shells that use legitimate HTTPS traffic for communication. I hope this project can be a starting point for penetration testers who desire this capability in their engagements.

Disclaimer: This reverse shell is for research purposes only, and should only be used on authorized systems. Accessing a computer system or network without authorization or explicit permission is illegal.

Server (Linux)

It's recommended not to use default values when creating a self-signed certificate as this could generate a certificate that will alert an IDS. Also, note that as the client/server is running you may modify static/command.html to the Windows command you wish to execute, or use python setcmd.py.

$ # clone this repository
$ git clone https://github.com/vesche/lonely-shell
$ # create a new directory for your server
$ mkdir server && cd $_
$ # generate a 2048-bit private key and a self-signed certificate
$ openssl req -newkey rsa:2048 -nodes -keyout server.key -x509 -days 365 -out server.crt
$ # create the static directory
$ mkdir static
$ # write a windows command to command.html for the client to GET
$ echo "dir" > static/command.html
$ # copy server.go into your server directory
$ cp ../lonely-shell/server.go .
$ # build the server
$ go build server.go
$ # start the server
$ sudo ./server

Client (Windows)

You will need to modify the IP address in client.go to fit your needs. It's required to first build the client normally, and then build it with the switch options to hide the command prompt window. Double clicking the binary will start the client, given there is a properly configured server. The client has only been tested on Windows 7, but should work on XP - 10.

C:\> :: clone this repository
C:\> git clone https://github.com/vesche/lonely-shell && cd lonely-shell
C:\lonely-shell> :: build the client
C:\lonely-shell> go build client.go
C:\lonely-shell> :: rebuild the client so it will run in a hidden window
C:\lonely-shell> go build -ldflags -H=windowsgui client.go
C:\lonely-shell> :: start the client
C:\lonely-shell> client.exe