mirror of
https://github.com/DarkWebInformer/vect-ransomware-decryptor.git
synced 2026-06-08 11:25:27 +00:00
Dark Web Informer
359 lines
8.0 KiB
Go
359 lines
8.0 KiB
Go
package main
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import (
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"encoding/hex"
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"flag"
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"fmt"
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"io/fs"
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"os"
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"path/filepath"
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"strings"
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"unicode"
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"golang.org/x/crypto/chacha20poly1305"
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)
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const (
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nonceSize = 12
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tagSize = 16
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overhead = nonceSize + tagSize
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blockSize = 0x100000
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encExt = ".vect1"
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hexRows = 4
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)
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func hexdump(label string, data []byte) {
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n := hexRows * 16
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if len(data) < n {
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n = len(data)
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}
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chunk := data[:n]
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fmt.Printf(" %-6s offset 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f │ ASCII\n", label)
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fmt.Printf(" ------ ------ ----------------------------------------------- │ ----------------\n")
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for i := 0; i < len(chunk); i += 16 {
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j := i + 16
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if j > len(chunk) {
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j = len(chunk)
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}
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row := chunk[i:j]
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fmt.Printf(" %06x ", i)
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for k := 0; k < 16; k++ {
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if k == 8 {
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fmt.Print(" ")
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}
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if k < len(row) {
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fmt.Printf("%02x ", row[k])
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} else {
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fmt.Print(" ")
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}
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}
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fmt.Print(" │ ")
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for _, b := range row {
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if b < 128 && unicode.IsPrint(rune(b)) {
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fmt.Printf("%c", b)
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} else {
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fmt.Print(".")
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}
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}
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fmt.Println()
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}
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if len(data) > hexRows*16 {
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fmt.Printf(" ... (%d bytes total)\n", len(data))
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}
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fmt.Println()
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}
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func decryptBlock(key, nonce, ctAndTag []byte) ([]byte, bool) {
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aead, err := chacha20poly1305.New(key)
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if err != nil {
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return nil, false
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}
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out, err := aead.Open(nil, nonce, ctAndTag, nil)
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if err != nil {
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return nil, false
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}
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return out, true
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}
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func readTestBlock(path string) (nonce []byte, ctAndTag []byte, err error) {
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f, err := os.Open(path)
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if err != nil {
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return nil, nil, err
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}
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defer f.Close()
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buf := make([]byte, nonceSize+blockSize+tagSize)
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n, err := f.Read(buf)
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if err != nil && n == 0 {
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return nil, nil, err
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}
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buf = buf[:n]
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if len(buf) < overhead+1 {
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return nil, nil, fmt.Errorf("file too small to use as oracle")
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}
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return buf[:nonceSize], buf[nonceSize:], nil
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}
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func extractKey(binaryPath, samplePath string) ([]byte, error) {
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nonce, ctAndTag, err := readTestBlock(samplePath)
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if err != nil {
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return nil, fmt.Errorf("reading sample: %w", err)
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}
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raw, err := os.ReadFile(binaryPath)
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if err != nil {
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return nil, fmt.Errorf("reading binary: %w", err)
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}
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window := len(raw) - 32 + 1
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if window <= 0 {
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return nil, fmt.Errorf("binary too small")
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}
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fmt.Printf("[*] Scanning %d bytes (%d candidates)...\n", len(raw), window)
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for at := 0; at < window; at++ {
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k := raw[at : at+32]
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if _, ok := decryptBlock(k, nonce, ctAndTag); ok {
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fmt.Printf("[+] Key found at binary offset 0x%08x\n", at)
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out := make([]byte, 32)
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copy(out, k)
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return out, nil
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}
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}
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return nil, fmt.Errorf("key not found in binary")
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}
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func decryptFile(key []byte, encPath string, backup, dump bool) bool {
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if !strings.HasSuffix(encPath, encExt) {
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return false
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}
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decPath := strings.TrimSuffix(encPath, encExt)
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st, err := os.Stat(encPath)
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if err != nil {
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fmt.Printf("[-] Stat failed: %s\n", encPath)
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return false
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}
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size := st.Size()
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if size < overhead {
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fmt.Printf("[-] Too small: %s\n", encPath)
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return false
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}
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body, err := os.ReadFile(encPath)
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if err != nil {
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fmt.Printf("[-] Read failed: %s\n", encPath)
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return false
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}
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if backup {
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_ = os.WriteFile(encPath+".bak", body, 0644)
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}
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fmt.Printf("\n[>] %s\n", filepath.Base(encPath))
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if dump {
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fmt.Printf(" Nonce: %s\n\n", hex.EncodeToString(body[:nonceSize]))
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hexdump("BEFORE", body[nonceSize:])
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}
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var plain []byte
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if size <= blockSize+overhead {
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p, ok := decryptBlock(key, body[:nonceSize], body[nonceSize:])
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if !ok {
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fmt.Printf("[-] Auth failure (wrong key?): %s\n", filepath.Base(encPath))
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return false
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}
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plain = p
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} else {
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endFirst := int64(blockSize + overhead)
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head, ok := decryptBlock(key, body[:nonceSize], body[nonceSize:endFirst])
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if !ok {
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fmt.Printf("[-] Auth failure (wrong key?): %s\n", filepath.Base(encPath))
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return false
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}
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tailOff := size - overhead
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mid := body[endFirst:tailOff]
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tail := body[tailOff:]
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z := make([]byte, overhead)
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plain = head
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plain = append(plain, z...)
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plain = append(plain, mid...)
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plain = append(plain, tail...)
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wantLen := size - overhead
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if int64(len(plain)) > wantLen {
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plain = plain[:wantLen]
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}
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}
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if dump {
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hexdump("AFTER", plain)
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}
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if err := os.WriteFile(encPath, plain, 0644); err != nil {
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fmt.Printf("[-] Write failed: %s\n", encPath)
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return false
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}
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if err := os.Rename(encPath, decPath); err != nil {
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fmt.Printf("[-] Rename failed (%v): %s\n", err, encPath)
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return false
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}
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fmt.Printf("[+] %s -> %s (%d bytes)\n",
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filepath.Base(encPath), filepath.Base(decPath), len(plain))
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return true
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}
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func decryptDirectory(key []byte, dir string, backup, dump bool) (ok, failed int) {
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_ = filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
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if err != nil || d.IsDir() {
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return nil
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}
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if strings.HasSuffix(path, encExt) {
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if decryptFile(key, path, backup, dump) {
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ok++
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} else {
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failed++
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}
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}
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return nil
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})
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return ok, failed
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}
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func usage() {
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fmt.Println(`Usage:
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vect1_decryptor extract-key -binary locker.exe -sample file.vect1 [-out key.txt]
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vect1_decryptor decrypt -target <path> -key <hex64> [-backup] [-hexdump]
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vect1_decryptor auto -binary locker.exe -target <dir> [-backup] [-hexdump]`)
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os.Exit(1)
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}
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func main() {
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if len(os.Args) < 2 {
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usage()
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}
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cmd := os.Args[1]
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args := os.Args[2:]
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switch cmd {
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case "extract-key":
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fl := flag.NewFlagSet("extract-key", flag.ExitOnError)
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binary := fl.String("binary", "", "")
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sample := fl.String("sample", "", "")
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outPath := fl.String("out", "", "")
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fl.Parse(args)
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if *binary == "" || *sample == "" {
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fmt.Println("[-] -binary and -sample are required.")
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fl.Usage()
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os.Exit(1)
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}
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key, err := extractKey(*binary, *sample)
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if err != nil {
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fmt.Printf("[-] %v\n", err)
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os.Exit(1)
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}
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keyHex := hex.EncodeToString(key)
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fmt.Printf("[+] Key (hex): %s\n", keyHex)
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if *outPath != "" {
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err := os.WriteFile(*outPath, []byte(keyHex), 0600)
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if err != nil {
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fmt.Printf("[-] Could not save key: %v\n", err)
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} else {
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fmt.Printf("[+] Saved to %s\n", *outPath)
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}
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}
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case "decrypt":
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fl := flag.NewFlagSet("decrypt", flag.ExitOnError)
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path := fl.String("target", "", "")
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keyHex := fl.String("key", "", "")
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backup := fl.Bool("backup", false, "")
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dump := fl.Bool("hexdump", false, "")
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fl.Parse(args)
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if *path == "" || *keyHex == "" {
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fmt.Println("[-] -target and -key are required.")
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fl.Usage()
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os.Exit(1)
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}
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key, err := hex.DecodeString(*keyHex)
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if err != nil || len(key) != 32 {
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fmt.Println("[-] Key must be exactly 64 hex characters (32 bytes).")
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os.Exit(1)
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}
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info, err := os.Stat(*path)
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if err != nil {
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fmt.Printf("[-] Target not found: %s\n", *path)
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os.Exit(1)
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}
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if info.IsDir() {
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ok, bad := decryptDirectory(key, *path, *backup, *dump)
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fmt.Printf("\n[*] Done: %d decrypted, %d failed\n", ok, bad)
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} else {
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decryptFile(key, *path, *backup, *dump)
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}
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case "auto":
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fl := flag.NewFlagSet("auto", flag.ExitOnError)
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binary := fl.String("binary", "", "")
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target := fl.String("target", "", "")
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backup := fl.Bool("backup", false, "")
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dump := fl.Bool("hexdump", false, "")
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fl.Parse(args)
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if *binary == "" || *target == "" {
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fmt.Println("[-] -binary and -target are required.")
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fl.Usage()
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os.Exit(1)
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}
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var sample string
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_ = filepath.WalkDir(*target, func(p string, d fs.DirEntry, walkErr error) error {
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if walkErr != nil || d.IsDir() || sample != "" {
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return nil
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}
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if strings.HasSuffix(p, encExt) {
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sample = p
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}
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return nil
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})
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if sample == "" {
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fmt.Printf("[-] No %s files found in %s\n", encExt, *target)
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os.Exit(1)
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}
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fmt.Printf("[*] Using %s as decryption oracle\n", filepath.Base(sample))
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key, err := extractKey(*binary, sample)
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if err != nil {
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fmt.Printf("[-] %v\n", err)
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os.Exit(1)
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}
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fmt.Printf("[+] Key: %s\n", hex.EncodeToString(key))
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ok, bad := decryptDirectory(key, *target, *backup, *dump)
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fmt.Printf("\n[*] Done: %d decrypted, %d failed\n", ok, bad)
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default:
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fmt.Printf("[-] Unknown command: %s\n", cmd)
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usage()
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}
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}
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