> For the complete documentation index, see [llms.txt](https://capcap-1.gitbook.io/capcap/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://capcap-1.gitbook.io/capcap/readme/ctf-modules/exploitation/password-attacks/cracking-protected-archives.md).

# Cracking Protected Archives

## Cracking Protected Archives

### Overview

Different archive/encryption types need different cracking approaches. The general rule:

* If the format **natively supports passwords** → use `*2john` to extract hash → crack offline
* If the format **doesn't natively support passwords** (e.g. openssl-encrypted GZIP) → brute-force directly
* Full disk encryption (BitLocker) → specialized extraction tool → hashcat

***

### Finding Archive Files on a Target

```bash
# Pull full list of compressed file extensions from FileInfo
curl -s https://fileinfo.com/filetypes/compressed | html2text | awk '{print tolower($1)}' | grep "\." | tee -a compressed_ext.txt
```

Common archive extensions to look for manually: `.zip .rar .7z .tar .gz .tar.gz .bz2 .kdbx .vhd .vmdk .cpt`

> Note: Not all archive formats support native password protection. TAR/GZIP use external tools like `openssl` or `gpg` for encryption.

***

### 1. Cracking ZIP Files

ZIP natively supports password protection — standard `*2john` workflow.

```bash
# Extract hash
zip2john ZIP.zip > zip.hash

# Inspect the hash (optional)
cat zip.hash
# $pkzip2$... — JtR auto-detects format, no --format needed

# Crack
john --wordlist=/usr/share/wordlists/rockyou.txt zip.hash

# Show result
john zip.hash --show
```

***

### 2. Cracking OpenSSL Encrypted GZIP

GZIP has no native password protection. When encrypted with openssl, there's no hash to extract — you brute-force decryption directly.

#### Identify the file type first

```bash
file GZIP.gzip
# Output: GZIP.gzip: openssl enc'd data with salted password
```

#### Brute-force with openssl loop

```bash
for i in $(cat /usr/share/wordlists/rockyou.txt);do openssl enc -aes-256-cbc -d -in GZIP.gzip -k $i 2>/dev/null | tar xz;done
```

What each part does:

| Part                          | Meaning                                              |
| ----------------------------- | ---------------------------------------------------- |
| `for i in $(cat rockyou.txt)` | Loop through every password                          |
| `openssl enc -aes-256-cbc -d` | Attempt AES-256 decryption                           |
| `-in GZIP.gzip`               | Target file                                          |
| `-k $i`                       | Current password attempt                             |
| `2>/dev/null`                 | Suppress errors from wrong passwords                 |
| `\| tar xz`                   | Pipe decrypted output into tar — extracts if correct |

You'll see repeated errors — that's normal, just wrong passwords failing. When the correct password hits, a file silently extracts.

```bash
# Check for extracted file after loop finishes
ls
```

> \**Why no 2john here?* OpenSSL encryption produces a binary blob with no standard hash structure inside. Every attempt requires a full decryption — slower than offline hash cracking, CPU only.

***

### 3. Cracking BitLocker Encrypted Drives

BitLocker = Windows full disk encryption (AES-128 or AES-256). Common on enterprise laptops and virtual drives (`.vhd` files).

Two unlock methods:

* **Password** — what you crack
* **Recovery key** — 48-digit random number, impractical to brute-force

#### Extract hashes

```bash
bitlocker2john -i Backup.vhd > backup.hashes

# Filter just the password hash ($bitlocker$0$...)
grep "bitlocker\$0" backup.hashes > backup.hash
```

> `bitlocker2john` produces 4 hashes — first two are password hashes, last two are recovery key hashes. Only target `$bitlocker$0$`.

#### Crack with hashcat

```bash
hashcat -a 0 -m 22100 backup.hash /usr/share/wordlists/rockyou.txt
```

> BitLocker uses high iteration AES — expect \~25 H/s on CPU. Very slow without GPU. Use hashcat, not JtR.

***

#### Mounting after cracking

**Windows:** Double-click `.vhd` → mount → double-click BitLocker volume → enter cracked password.

**Linux (dislocker):**

```bash
# Install
sudo apt-get install dislocker

# Create mount points
sudo mkdir -p /media/bitlocker
sudo mkdir -p /media/bitlockermount

# Attach VHD as loop device
sudo losetup -f -P Backup.vhd

# Decrypt with cracked password
sudo dislocker /dev/loop0p2 -u<password> -- /media/bitlocker

# Mount decrypted volume
sudo mount -o loop /media/bitlocker/dislocker-file /media/bitlockermount

# Browse
cd /media/bitlockermount && ls -la

# Unmount when done
sudo umount /media/bitlockermount
sudo umount /media/bitlocker
```

***

### Quick Reference — Tool by File Type

| File type     | Extract hash           | Crack with         | Hashcat mode  |
| ------------- | ---------------------- | ------------------ | ------------- |
| ZIP           | `zip2john`             | JtR / hashcat      | `13600`       |
| RAR           | `rar2john`             | JtR / hashcat      | `13000`       |
| 7z            | `7z2john.pl`           | JtR / hashcat      | `11600`       |
| OpenSSL GZIP  | No hash — openssl loop | `openssl` for loop | N/A           |
| BitLocker VHD | `bitlocker2john`       | hashcat            | `22100`       |
| Office docs   | `office2john.py`       | JtR / hashcat      | `9600` (docx) |
| PDF           | `pdf2john.py`          | JtR / hashcat      | `10500`       |
| SSH key       | `ssh2john`             | JtR / hashcat      | N/A           |
| KeePass       | `keepass2john`         | JtR / hashcat      | `13400`       |


---

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