# pseudodisk

A comprehensive toolkit for creating disk images with various filesystems for forensic analysis practice and education.

## Features

- **Multiple Filesystem Support**: NTFS, FAT32, exFAT, ext2/3/4, XFS, HFS+, swap
- **Preset Layouts**: Pre-configured layouts for Windows, Linux, and macOS systems
- **Multi-Partition Support**: Create up to 4 partitions in a single disk image
- **Partition Schemes**: GPT (modern) and MBR (legacy)
- **Initialization Methods**: Choose between /dev/zero (fast), /dev/urandom (realistic), or fallocate (sparse)
- **Interactive Configuration**: User-friendly prompts for all parameters
- **Automatic Loop Device Management**: Handles mounting and cleanup
- **Filesystem Availability Check**: Verifies required tools before operation
- **Forensic-Ready**: Pre-configured for hex editor and forensic tool analysis

## Prerequisites

### Required Packages

```bash
sudo apt-get update
sudo apt-get install -y \
    parted \
    util-linux \
    e2fsprogs \
    dosfstools \
    bc
```

### Optional (for specific filesystems)

```bash
# For NTFS support
sudo apt-get install ntfs-3g

# For exFAT support
sudo apt-get install exfat-fuse exfat-utils

# For XFS support
sudo apt-get install xfsprogs

# For HFS+ support
sudo apt-get install hfsprogs
```

## Preset Layouts

Choose from pre-configured layouts that simulate real operating systems:

**Windows Presets:**
- Windows 11/10 (GPT, EFI + NTFS + Recovery)
- Windows Vista/7/8 (MBR, System Reserved + NTFS)
- Windows 2000/XP (MBR, Single NTFS)
- Windows 98/ME (MBR, Single FAT32)
- Windows 95 (MBR, Single FAT16)
- Windows 3.1 (MBR, Single FAT16)
- MS-DOS (MBR, Single FAT12)

**Linux Presets:**
- Modern Linux (GPT, EFI + Root + Swap)
- Linux with /home (GPT, EFI + Root + Home)
- Classic Linux (MBR, Boot + Root + Swap)
- Minimal Linux (MBR, Single ext4)

**macOS Presets:**
- macOS (GPT, EFI + HFS+)

**Custom Layout:**
- Full manual configuration with 1-4 partitions

All presets can be customized during setup or used as-is.

## Initialization Methods

The script offers three methods for creating the disk image file:

1. **`/dev/zero`** (Recommended for most cases)
   - Fast creation speed
   - Fills image with zeros
   - Forensically predictable and clean
   - Creates realistic empty disk structure

2. **`/dev/urandom`** (For realistic random data)
   - Slow creation speed
   - Fills image with random data
   - More realistic for testing data recovery
   - Useful for simulating previously used disks

3. **`fallocate`** (Fastest)
   - Very fast, creates sparse file
   - Does not actually write data to disk initially
   - Good for quick testing
   - May not be suitable for all forensic scenarios

## Usage

### Creating a Disk Image

Run the main script with sudo:

```bash
sudo ./pseudodisk.sh
```

The script will:
1. Check filesystem tool availability
2. Interactively prompt you for:
   - **Filename**: Output file name (default: forensic_disk.dd)
   - **Size**: Choose from presets (100MB, 500MB, 1GB, 5GB, 10GB) or custom
   - **Initialization Method**: /dev/zero, /dev/urandom, or fallocate
   - **Layout**: Select a preset or custom configuration
   - **For Presets**: Option to use as-is or customize
   - **For Custom**:
     - Partition Scheme: GPT or MBR
     - Partition Count: 1-4 partitions
     - Per-Partition Configuration:
       - Filesystem type (NTFS, FAT32, exFAT, ext2/3/4, XFS, HFS+, swap, etc.)
       - Size in MB (last partition uses remaining space)
       - Volume label (except for swap)
   - **Mount**: Option to mount filesystems immediately after creation

### Example Session (with Preset)

```
==========================================
  Forensic Disk Image Creator
  Enhanced Edition v2.1
==========================================

Checking filesystem tool availability...

  ✓ FAT12/16 (mkfs.fat available)
  ✓ FAT32   (mkfs.vfat available)
  ✓ exFAT   (mkfs.exfat available)
  ✓ NTFS    (mkfs.ntfs available)
  ✓ ext2    (mke2fs/mkfs.ext2 available)
  ✓ ext3    (mke2fs/mkfs.ext3 available)
  ✓ ext4    (mkfs.ext4 available)
  ✓ XFS     (mkfs.xfs available)
  ✓ HFS+    (mkfs.hfsplus available)
  ✓ swap    (mkswap available)
  ✓ Unallocated (no mkfs required)

Enter output filename (default: forensic_disk.dd): win11.dd

Disk Size Options:
  1) 100 MB  (small, quick testing)
  2) 500 MB  (medium)
  3) 1 GB    (standard)
  4) 5 GB    (large)
  5) 10 GB   (very large)
  6) Custom size

Select disk size [1-6]: 3

Initialization Method:
  1) /dev/zero   (Fast, zeros - forensically predictable)
  2) /dev/urandom (Slow, random data - more realistic)
  3) fallocate   (Fastest, sparse file)

Select initialization method [1-3]: 1

==========================================
  Disk Layout
==========================================

Layout Presets:

  Windows Presets:
    1)  Windows 11/10 (GPT, EFI + NTFS + Recovery)
    2)  Windows Vista/7/8 (MBR, System Reserved + NTFS)
    3)  Windows 2000/XP (MBR, Single NTFS)
    4)  Windows 98/ME (MBR, Single FAT32)
    5)  Windows 95 (MBR, Single FAT16)
    6)  Windows 3.1 (MBR, Single FAT16)
    7)  MS-DOS (MBR, Single FAT12)

  Linux Presets:
    8)  Modern Linux (GPT, EFI + Root + Swap)
    9)  Linux with /home (GPT, EFI + Root + Home)
    10) Classic Linux (MBR, Boot + Root + Swap)
    11) Minimal Linux (MBR, Single ext4)

  macOS Presets:
    12) macOS (GPT, EFI + HFS+)

  Custom:
    13) Custom layout (manual configuration)

Select layout [1-13]: 1

[INFO] Preset: Windows 11/10 (GPT)
[NOTE] EFI System Partition (260MB) + Main Windows (auto) + Recovery (500MB)

Customize this preset? (y/n, default: n): n
[INFO] Using preset configuration as-is
```

### Cleaning Up

When finished with your analysis, use the cleanup script:

```bash
# Clean up a specific disk image
sudo ./cleanup.sh
# Enter filename when prompted

# Or clean up all loop devices
sudo ./cleanup.sh
# Type 'all' when prompted
```

## Forensic Analysis Guide

### Basic Hex Analysis

#### View raw disk structure
```bash
# Using hexdump
hexdump -C win11.dd | less

# Using xxd
xxd win11.dd | less

# View first 512 bytes (boot sector)
xxd -l 512 win11.dd

# View specific offset (e.g., partition table at 0x1BE for MBR)
xxd -s 0x1BE -l 64 win11.dd
```

#### GUI Hex Editors
```bash
# Install Bless (GTK hex editor)
sudo apt-get install bless
bless win11.dd

# Or install GHex
sudo apt-get install ghex
ghex win11.dd

# Or install wxHexEditor (advanced)
sudo apt-get install wxhexeditor
wxhexeditor win11.dd
```

### Partition Analysis

```bash
# View partition table
sudo parted win11.dd print

# Or using fdisk
sudo fdisk -l win11.dd

# For GPT, use gdisk
sudo apt-get install gdisk
sudo gdisk -l win11.dd
```

### Using The Sleuth Kit (TSK)

```bash
# Install if not already present
sudo apt-get install sleuthkit

# Display partition layout
mmls win11.dd

# Show filesystem details (offset from mmls output)
fsstat -o 2048 win11.dd

# List files in filesystem
fls -o 2048 -r win11.dd

# Display file content by inode
icat -o 2048 win11.dd [inode_number]

# Show deleted files
fls -o 2048 -rd win11.dd

# Timeline analysis
fls -o 2048 -m / -r win11.dd > timeline.bodyfile
mactime -b timeline.bodyfile
```

### Manual Loop Device Management

If you need more control over the loop device:

```bash
# Attach image to loop device
sudo losetup -f win11.dd

# List all loop devices
sudo losetup -l

# Find out which loop device is attached
sudo losetup -j win11.dd

# Mount the partition
sudo mkdir -p /mnt/forensic
sudo mount /dev/loop0p1 /mnt/forensic

# When done, unmount
sudo umount /mnt/forensic

# Detach loop device
sudo losetup -d /dev/loop0
```

### Filesystem-Specific Analysis

#### NTFS Analysis

```bash
# View NTFS volume information
sudo apt-get install ntfs-3g
sudo ntfsinfo -m /dev/loop0p1

# Show NTFS file system usage
sudo ntfscluster -f /dev/loop0p1

# Recover deleted files
sudo apt-get install testdisk
sudo testdisk win11.dd
```

#### FAT32 Analysis

```bash
# View FAT information
sudo fsck.vfat -n /dev/loop0p1

# Or using sleuthkit
fsstat -o 2048 win11.dd
```

#### ext4 Analysis

```bash
# Dump ext4 superblock
sudo dumpe2fs /dev/loop0p1

# Check filesystem
sudo e2fsck -n /dev/loop0p1

# Show inode information
sudo debugfs -R 'stat <inode>' /dev/loop0p1
```

## Key Forensic Structures to Examine

### Master Boot Record (MBR)
- **Location**: First 512 bytes (0x000-0x1FF)
- **Boot Code**: 0x000-0x1BD (446 bytes)
- **Partition Table**: 0x1BE-0x1FD (64 bytes, 4 entries × 16 bytes)
- **Signature**: 0x1FE-0x1FF (0x55AA)

### GUID Partition Table (GPT)
- **Protective MBR**: Sector 0 (0x000-0x1FF)
- **GPT Header**: Sector 1 (0x200-0x3FF)
- **Partition Entries**: Sectors 2-33 (typically)
- **Backup GPT**: Last sectors of disk

### NTFS Boot Sector
- **Jump Instruction**: 0x000-0x002
- **OEM ID**: 0x003-0x00A ("NTFS    ")
- **Bytes Per Sector**: 0x00B-0x00C
- **Sectors Per Cluster**: 0x00D
- **MFT Location**: 0x030-0x037
- **Signature**: 0x1FE-0x1FF (0x55AA)

### FAT32 Boot Sector
- **Jump Instruction**: 0x000-0x002
- **OEM Name**: 0x003-0x00A
- **Bytes Per Sector**: 0x00B-0x00C
- **Sectors Per Cluster**: 0x00D
- **FAT Copies**: 0x010
- **Signature**: 0x1FE-0x1FF (0x55AA)

## Practice Exercises

### Beginner Level

1. **Identify Partition Scheme**
   - Create disks with different Windows versions (MBR vs GPT)
   - Compare the first 512 bytes
   - Identify the signature differences

2. **Find the Filesystem Type**
   - Create disks with different filesystems using presets
   - Examine boot sector signatures
   - Identify OEM strings

3. **Locate Partition Boundaries**
   - Use hexdump to find partition start
   - Verify with `parted` output

### Intermediate Level

4. **File Recovery Practice**
   - Mount filesystem, create files, unmount
   - Delete files from another mount
   - Practice recovering deleted files

5. **Metadata Analysis**
   - Create files with specific timestamps
   - Use TSK to extract timeline data
   - Correlate timestamps with hex data

6. **Slack Space Investigation**
   - Create small files in large clusters
   - Examine slack space for data remnants
   - Understand cluster allocation

### Advanced Level

7. **Steganography Detection**
   - Hide data in slack space
   - Practice identifying hidden data
   - Compare expected vs actual cluster usage

8. **Partition Hiding**
    - Create multiple partitions
    - Modify partition table
    - Practice recovering hidden partitions

9. **Anti-Forensics Techniques**
   - Study timestamp manipulation
   - Examine wiping patterns
   - Analyze file system corruption

10. **Cross-OS Analysis**
    - Create Windows and Linux dual-boot layout
    - Analyze different partition schemes
    - Practice identifying filesystem boundaries

## Troubleshooting

### Loop device not found
```bash
# Ensure loop module is loaded
sudo modprobe loop

# Check available loop devices
ls -la /dev/loop*
```

### Permission denied
```bash
# Always use sudo for these operations
sudo ./pseudodisk.sh
```

### Partition not showing up
```bash
# Force kernel to re-read partition table
sudo partprobe /dev/loopX

# Or detach and re-attach
sudo losetup -d /dev/loopX
sudo losetup -f win11.dd
```

### Cannot unmount - device busy
```bash
# Find what's using it
sudo lsof | grep /mnt/forensic

# Force unmount (use with caution)
sudo umount -l /mnt/forensic
```

## Notes on Filesystem Support

- **NTFS**: Full read/write support via ntfs-3g
- **FAT12/16/32**: Full support on all Linux systems
- **exFAT**: Requires exfatprogs or exfat-utils
- **ext2/3/4**: Native Linux support
- **XFS**: Native Linux support
- **HFS+**: Limited support (often read-only on Linux)
- **APFS**: Not supported on Linux (requires macOS)