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Sleuth Kit Cheat Sheet ​

Overview ​

The Sleuth Kit (TSK) is a comprehensive collection of command-line digital forensics tools that enables investigators to analyze disk images and file systems to recover digital evidence. Developed by Brian Carrier, TSK serves as the foundation for many digital forensics platforms, including Autopsy, and provides low-level access to file system structures and metadata. The toolkit supports multiple file systems including NTFS, FAT, ext2/3/4, HFS+, and UFS, making it versatile for analyzing evidence from various operating systems and storage devices.

TSK's strength lies in its modular architecture and command-line interface, which allows for precise control over forensic analysis processes and enables automation through scripting. The toolkit includes tools for file system analysis, timeline creation, metadata extraction, deleted file recovery, and hash calculation. Its ability to work directly with raw disk images and file system structures makes it invaluable for detailed forensic examinations where GUI tools may not provide sufficient granular control.

The Sleuth Kit has become the de facto standard for command-line digital forensics, widely adopted by law enforcement agencies, corporate security teams, and incident response professionals. Its open-source nature and extensive documentation have made it a cornerstone of digital forensics education and research. The toolkit's integration capabilities with other forensic tools and its support for various output formats make it an essential component of comprehensive digital forensics workflows.

Installation ​

Package Manager Installation ​

Installing TSK through system package managers:

bash
# Ubuntu/Debian installation
sudo apt update
sudo apt install sleuthkit

# Kali Linux (pre-installed)
tsk_recover --help

# CentOS/RHEL installation
sudo yum install epel-release
sudo yum install sleuthkit

# Arch Linux installation
sudo pacman -S sleuthkit

# macOS installation
brew install sleuthkit

# Verify installation
mmls --version
fls --version

Source Compilation ​

Compiling TSK from source code:

bash
# Install dependencies
sudo apt install build-essential autoconf automake libtool
sudo apt install libafflib-dev libewf-dev zlib1g-dev

# Download source code
wget https://github.com/sleuthkit/sleuthkit/releases/download/sleuthkit-4.12.0/sleuthkit-4.12.0.tar.gz
tar -xzf sleuthkit-4.12.0.tar.gz
cd sleuthkit-4.12.0

# Configure build
./configure --enable-java --with-afflib --with-libewf

# Compile and install
make
sudo make install

# Update library cache
sudo ldconfig

# Verify installation
mmls --version

Docker Installation ​

bash
# Create TSK Docker environment
cat > Dockerfile << 'EOF'
FROM ubuntu:20.04
ENV DEBIAN_FRONTEND=noninteractive

RUN apt-get update && apt-get install -y \
    sleuthkit libewf-tools afflib-tools \
    python3 python3-pip file hexdump

WORKDIR /evidence
CMD ["/bin/bash"]
EOF

# Build container
docker build -t sleuthkit-forensics .

# Run with evidence mounted
docker run -it -v $(pwd)/evidence:/evidence sleuthkit-forensics

# Example usage in container
docker run -it sleuthkit-forensics mmls /evidence/disk_image.dd

Basic Usage ​

Disk Image Analysis ​

Analyzing disk images and partition structures:

bash
# Display partition table
mmls disk_image.dd

# Display detailed partition information
mmls -t dos disk_image.dd
mmls -t gpt disk_image.dd
mmls -t mac disk_image.dd

# Display partition table with sector offsets
mmls -a disk_image.dd

# Analyze specific partition
mmls -o 2048 disk_image.dd

# Display file system information
fsstat -o 2048 disk_image.dd

File System Analysis ​

Analyzing file systems and directory structures:

bash
# List files in root directory
fls -o 2048 disk_image.dd

# List files recursively
fls -r -o 2048 disk_image.dd

# List deleted files
fls -d -o 2048 disk_image.dd

# List files with full paths
fls -p -o 2048 disk_image.dd

# List files with metadata
fls -l -o 2048 disk_image.dd

# List files in specific directory (inode)
fls -o 2048 disk_image.dd 1234

File Recovery ​

Recovering files and analyzing file content:

bash
# Extract file by inode
icat -o 2048 disk_image.dd 5678 > recovered_file.txt

# Extract file with metadata preservation
icat -s -o 2048 disk_image.dd 5678 > recovered_file.txt

# Display file metadata
istat -o 2048 disk_image.dd 5678

# Display directory entry information
ffind -o 2048 disk_image.dd 5678

# Find files by name
ffind -n filename -o 2048 disk_image.dd

Advanced Features ​

Timeline Analysis ​

Creating and analyzing file system timelines:

bash
# Create timeline in body format
fls -r -m / -o 2048 disk_image.dd > timeline.body

# Create timeline with deleted files
fls -r -d -m / -o 2048 disk_image.dd >> timeline.body

# Convert body file to timeline
mactime -b timeline.body -d > timeline.csv

# Create timeline for specific date range
mactime -b timeline.body -d 2024-01-01..2024-01-31 > january_timeline.csv

# Create timeline with time zone
mactime -b timeline.body -d -z EST5EDT > timeline_est.csv

# Create timeline in different formats
mactime -b timeline.body -d -m > timeline_monthly.csv

Deleted File Recovery ​

Advanced deleted file recovery techniques:

bash
# List all deleted files
fls -d -r -o 2048 disk_image.dd

# Recover deleted files by pattern
fls -d -r -o 2048 disk_image.dd | grep "\.doc$"

# Recover deleted file content
icat -o 2048 disk_image.dd 1234-128-1 > deleted_file.doc

# Search for file signatures in unallocated space
blkls -o 2048 disk_image.dd | sigfind -t jpeg

# Carve files from unallocated space
blkls -o 2048 disk_image.dd | foremost -t all -i -

# Search for specific strings in unallocated space
blkls -o 2048 disk_image.dd | strings | grep "password"

Hash Analysis ​

File hash calculation and verification:

bash
# Calculate MD5 hashes for all files
fls -r -o 2048 disk_image.dd | while read line; do
    inode=$(echo $line | awk '{print $2}' | cut -d: -f1)
    filename=$(echo $line | awk '{print $3}')
    if [[ $inode =~ ^[0-9]+$ ]]; then
        hash=$(icat -o 2048 disk_image.dd $inode | md5sum | cut -d' ' -f1)
        echo "$hash  $filename"
    fi
done > file_hashes.md5

# Calculate SHA-256 hashes
fls -r -o 2048 disk_image.dd | while read line; do
    inode=$(echo $line | awk '{print $2}' | cut -d: -f1)
    filename=$(echo $line | awk '{print $3}')
    if [[ $inode =~ ^[0-9]+$ ]]; then
        hash=$(icat -o 2048 disk_image.dd $inode | sha256sum | cut -d' ' -f1)
        echo "$hash  $filename"
    fi
done > file_hashes.sha256

# Compare against known hash database
hashdeep -c sha256 -k known_hashes.txt file_hashes.sha256

Metadata Analysis ​

Analyzing file and file system metadata:

bash
# Display detailed file metadata
istat -o 2048 disk_image.dd 5678

# Display file system metadata
fsstat -o 2048 disk_image.dd

# Display journal information (ext3/4)
jls -o 2048 disk_image.dd

# Display journal entries
jcat -o 2048 disk_image.dd 1234

# Display NTFS MFT entries
istat -o 2048 disk_image.dd 0

# Analyze alternate data streams (NTFS)
fls -a -o 2048 disk_image.dd

Automation Scripts ​

Comprehensive Disk Analysis ​

bash
#!/bin/bash
# Comprehensive TSK disk analysis script

DISK_IMAGE="$1"
OUTPUT_DIR="tsk_analysis_$(date +%Y%m%d_%H%M%S)"

if [ -z "$DISK_IMAGE" ]; then
    echo "Usage: $0 <disk_image>"
    exit 1
fi

if [ ! -f "$DISK_IMAGE" ]; then
    echo "Error: Disk image file not found: $DISK_IMAGE"
    exit 1
fi

echo "Starting comprehensive TSK analysis of: $DISK_IMAGE"
echo "Output directory: $OUTPUT_DIR"

# Create output directory
mkdir -p "$OUTPUT_DIR"

# Step 1: Analyze partition table
echo "Step 1: Analyzing partition table..."
mmls "$DISK_IMAGE" > "$OUTPUT_DIR/partition_table.txt" 2>&1

# Extract partition information
PARTITIONS=$(mmls "$DISK_IMAGE" 2>/dev/null | grep -E "^[0-9]" | awk '{print $3}')

if [ -z "$PARTITIONS" ]; then
    echo "No partitions found, analyzing as single file system..."
    PARTITIONS="0"
fi

# Step 2: Analyze each partition
for OFFSET in $PARTITIONS; do
    echo "Step 2: Analyzing partition at offset $OFFSET..."
    
    PART_DIR="$OUTPUT_DIR/partition_$OFFSET"
    mkdir -p "$PART_DIR"
    
    # File system information
    echo "Getting file system information..."
    fsstat -o "$OFFSET" "$DISK_IMAGE" > "$PART_DIR/filesystem_info.txt" 2>&1
    
    # File listing
    echo "Creating file listing..."
    fls -r -p -o "$OFFSET" "$DISK_IMAGE" > "$PART_DIR/file_listing.txt" 2>&1
    
    # Deleted files
    echo "Listing deleted files..."
    fls -r -d -p -o "$OFFSET" "$DISK_IMAGE" > "$PART_DIR/deleted_files.txt" 2>&1
    
    # Timeline creation
    echo "Creating timeline..."
    fls -r -m "/" -o "$OFFSET" "$DISK_IMAGE" > "$PART_DIR/timeline.body" 2>&1
    fls -r -d -m "/" -o "$OFFSET" "$DISK_IMAGE" >> "$PART_DIR/timeline.body" 2>&1
    
    if [ -s "$PART_DIR/timeline.body" ]; then
        mactime -b "$PART_DIR/timeline.body" -d > "$PART_DIR/timeline.csv" 2>&1
    fi
    
    # Hash calculation for active files
    echo "Calculating file hashes..."
    fls -r -o "$OFFSET" "$DISK_IMAGE" | while IFS= read -r line; do
        if [[ $line =~ ^r/r ]]; then
            inode=$(echo "$line" | awk '{print $2}' | cut -d: -f1)
            filename=$(echo "$line" | awk '{print $3}')
            
            if [[ $inode =~ ^[0-9]+$ ]] && [ "$inode" != "0" ]; then
                hash=$(icat -o "$OFFSET" "$DISK_IMAGE" "$inode" 2>/dev/null | md5sum 2>/dev/null | cut -d' ' -f1)
                if [ ! -z "$hash" ]; then
                    echo "$hash  $filename"
                fi
            fi
        fi
    done > "$PART_DIR/file_hashes.md5"
    
    # Unallocated space analysis
    echo "Analyzing unallocated space..."
    blkls -o "$OFFSET" "$DISK_IMAGE" > "$PART_DIR/unallocated_space.raw" 2>&1
    
    # String extraction from unallocated space
    if [ -s "$PART_DIR/unallocated_space.raw" ]; then
        strings "$PART_DIR/unallocated_space.raw" > "$PART_DIR/unallocated_strings.txt"
        
        # Search for common patterns
        grep -i "password\|username\|email\|http\|ftp" "$PART_DIR/unallocated_strings.txt" > "$PART_DIR/interesting_strings.txt"
    fi
    
    echo "Completed analysis of partition at offset $OFFSET"
done

# Step 3: Generate summary report
echo "Step 3: Generating summary report..."
cat > "$OUTPUT_DIR/analysis_summary.txt" << EOF
TSK Analysis Summary
===================
Image File: $DISK_IMAGE
Analysis Date: $(date)
Output Directory: $OUTPUT_DIR

Partition Analysis:
EOF

for OFFSET in $PARTITIONS; do
    PART_DIR="$OUTPUT_DIR/partition_$OFFSET"
    
    if [ -d "$PART_DIR" ]; then
        echo "Partition Offset: $OFFSET" >> "$OUTPUT_DIR/analysis_summary.txt"
        
        if [ -f "$PART_DIR/file_listing.txt" ]; then
            file_count=$(wc -l < "$PART_DIR/file_listing.txt")
            echo "  Total Files: $file_count" >> "$OUTPUT_DIR/analysis_summary.txt"
        fi
        
        if [ -f "$PART_DIR/deleted_files.txt" ]; then
            deleted_count=$(wc -l < "$PART_DIR/deleted_files.txt")
            echo "  Deleted Files: $deleted_count" >> "$OUTPUT_DIR/analysis_summary.txt"
        fi
        
        if [ -f "$PART_DIR/file_hashes.md5" ]; then
            hash_count=$(wc -l < "$PART_DIR/file_hashes.md5")
            echo "  Files Hashed: $hash_count" >> "$OUTPUT_DIR/analysis_summary.txt"
        fi
        
        echo "" >> "$OUTPUT_DIR/analysis_summary.txt"
    fi
done

echo "Analysis completed successfully!"
echo "Results saved in: $OUTPUT_DIR"
echo "Summary report: $OUTPUT_DIR/analysis_summary.txt"

Automated File Recovery ​

python
#!/usr/bin/env python3
# Automated file recovery using TSK

import subprocess
import os
import re
import csv
from datetime import datetime

class TSKFileRecovery:
    def __init__(self, image_path, output_dir):
        self.image_path = image_path
        self.output_dir = output_dir
        self.partitions = []
        self.recovered_files = []
    
    def discover_partitions(self):
        """Discover partitions in disk image"""
        try:
            result = subprocess.run(['mmls', self.image_path], 
                                  capture_output=True, text=True)
            
            for line in result.stdout.split('\n'):
                if re.match(r'^\d+:', line):
                    parts = line.split()
                    if len(parts) >= 4:
                        offset = parts[2]
                        self.partitions.append(offset)
            
            if not self.partitions:
                self.partitions = ['0']  # Single file system
                
        except Exception as e:
            print(f"Error discovering partitions: {e}")
            self.partitions = ['0']
    
    def list_deleted_files(self, offset):
        """List deleted files in partition"""
        deleted_files = []
        
        try:
            cmd = ['fls', '-d', '-r', '-p', '-o', offset, self.image_path]
            result = subprocess.run(cmd, capture_output=True, text=True)
            
            for line in result.stdout.split('\n'):
                if line.strip() and not line.startswith('d/d'):
                    parts = line.split('\t')
                    if len(parts) >= 2:
                        inode_info = parts[0].split()
                        if len(inode_info) >= 2:
                            inode = inode_info[1].split(':')[0]
                            filename = parts[1] if len(parts) > 1 else 'unknown'
                            
                            deleted_files.append({
                                'inode': inode,
                                'filename': filename,
                                'full_line': line.strip()
                            })
        
        except Exception as e:
            print(f"Error listing deleted files: {e}")
        
        return deleted_files
    
    def recover_file(self, offset, inode, output_filename):
        """Recover individual file by inode"""
        try:
            output_path = os.path.join(self.output_dir, output_filename)
            
            # Create output directory if needed
            os.makedirs(os.path.dirname(output_path), exist_ok=True)
            
            cmd = ['icat', '-o', offset, self.image_path, inode]
            
            with open(output_path, 'wb') as f:
                result = subprocess.run(cmd, stdout=f, stderr=subprocess.PIPE)
            
            if result.returncode == 0 and os.path.getsize(output_path) > 0:
                return {
                    'status': 'success',
                    'output_path': output_path,
                    'size': os.path.getsize(output_path)
                }
            else:
                os.remove(output_path)
                return {
                    'status': 'failed',
                    'error': result.stderr.decode()
                }
                
        except Exception as e:
            return {
                'status': 'error',
                'error': str(e)
            }
    
    def get_file_metadata(self, offset, inode):
        """Get file metadata using istat"""
        try:
            cmd = ['istat', '-o', offset, self.image_path, inode]
            result = subprocess.run(cmd, capture_output=True, text=True)
            
            if result.returncode == 0:
                return result.stdout
            else:
                return None
                
        except Exception as e:
            print(f"Error getting metadata for inode {inode}: {e}")
            return None
    
    def recover_files_by_extension(self, extensions, max_files=100):
        """Recover files by file extension"""
        
        print(f"Starting file recovery for extensions: {extensions}")
        
        # Discover partitions
        self.discover_partitions()
        print(f"Found partitions at offsets: {self.partitions}")
        
        total_recovered = 0
        
        for offset in self.partitions:
            print(f"Processing partition at offset {offset}")
            
            # List deleted files
            deleted_files = self.list_deleted_files(offset)
            print(f"Found {len(deleted_files)} deleted files")
            
            # Filter by extension
            target_files = []
            for file_info in deleted_files:
                filename = file_info['filename'].lower()
                for ext in extensions:
                    if filename.endswith(f'.{ext.lower()}'):
                        target_files.append(file_info)
                        break
            
            print(f"Found {len(target_files)} files matching target extensions")
            
            # Recover files
            for i, file_info in enumerate(target_files[:max_files]):
                if total_recovered >= max_files:
                    break
                
                inode = file_info['inode']
                original_filename = file_info['filename']
                
                # Create safe filename
                safe_filename = re.sub(r'[^\w\-_\.]', '_', original_filename)
                output_filename = f"partition_{offset}/recovered_{i:04d}_{safe_filename}"
                
                print(f"Recovering file {i+1}/{len(target_files)}: {original_filename}")
                
                # Recover file
                recovery_result = self.recover_file(offset, inode, output_filename)
                
                # Get metadata
                metadata = self.get_file_metadata(offset, inode)
                
                # Record recovery result
                recovery_record = {
                    'partition_offset': offset,
                    'inode': inode,
                    'original_filename': original_filename,
                    'recovered_filename': output_filename,
                    'recovery_status': recovery_result['status'],
                    'file_size': recovery_result.get('size', 0),
                    'recovery_time': datetime.now().isoformat(),
                    'metadata': metadata
                }
                
                if recovery_result['status'] == 'success':
                    recovery_record['output_path'] = recovery_result['output_path']
                    total_recovered += 1
                else:
                    recovery_record['error'] = recovery_result.get('error', 'Unknown error')
                
                self.recovered_files.append(recovery_record)
        
        print(f"Recovery completed. Total files recovered: {total_recovered}")
        return self.recovered_files
    
    def generate_recovery_report(self):
        """Generate recovery report"""
        
        report_file = os.path.join(self.output_dir, 'recovery_report.csv')
        
        if not self.recovered_files:
            print("No recovery data to report")
            return
        
        # Write CSV report
        fieldnames = [
            'partition_offset', 'inode', 'original_filename', 
            'recovered_filename', 'recovery_status', 'file_size', 
            'recovery_time', 'output_path', 'error'
        ]
        
        with open(report_file, 'w', newline='') as csvfile:
            writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
            writer.writeheader()
            
            for record in self.recovered_files:
                # Remove metadata from CSV (too large)
                csv_record = {k: v for k, v in record.items() if k != 'metadata'}
                writer.writerow(csv_record)
        
        # Generate summary
        successful_recoveries = len([r for r in self.recovered_files if r['recovery_status'] == 'success'])
        total_attempts = len(self.recovered_files)
        
        summary = f"""
File Recovery Summary
====================
Image: {self.image_path}
Output Directory: {self.output_dir}
Recovery Date: {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}

Results:
- Total Recovery Attempts: {total_attempts}
- Successful Recoveries: {successful_recoveries}
- Failed Recoveries: {total_attempts - successful_recoveries}
- Success Rate: {(successful_recoveries/total_attempts*100):.1f}%

Detailed report saved to: {report_file}
"""
        
        summary_file = os.path.join(self.output_dir, 'recovery_summary.txt')
        with open(summary_file, 'w') as f:
            f.write(summary)
        
        print(summary)

# Usage
if __name__ == "__main__":
    image_path = "/evidence/disk_image.dd"
    output_dir = "/recovered_files"
    
    recovery = TSKFileRecovery(image_path, output_dir)
    
    # Recover common document types
    extensions = ['doc', 'docx', 'pdf', 'txt', 'jpg', 'png']
    recovered_files = recovery.recover_files_by_extension(extensions, max_files=50)
    
    # Generate report
    recovery.generate_recovery_report()

Timeline Analysis ​

python
#!/usr/bin/env python3
# TSK timeline analysis script

import subprocess
import csv
import json
from datetime import datetime, timedelta
from collections import defaultdict

class TSKTimelineAnalyzer:
    def __init__(self, image_path):
        self.image_path = image_path
        self.timeline_data = []
        self.analysis_results = {}
    
    def create_timeline(self, offset='0', output_file='timeline.csv'):
        """Create timeline using TSK tools"""
        
        print("Creating timeline from disk image...")
        
        # Create body file
        body_file = 'timeline.body'
        
        try:
            # Generate body file for active files
            cmd1 = ['fls', '-r', '-m', '/', '-o', offset, self.image_path]
            with open(body_file, 'w') as f:
                subprocess.run(cmd1, stdout=f, check=True)
            
            # Add deleted files to body file
            cmd2 = ['fls', '-r', '-d', '-m', '/', '-o', offset, self.image_path]
            with open(body_file, 'a') as f:
                subprocess.run(cmd2, stdout=f, check=True)
            
            # Convert body file to timeline
            cmd3 = ['mactime', '-b', body_file, '-d']
            with open(output_file, 'w') as f:
                result = subprocess.run(cmd3, stdout=f, text=True)
            
            if result.returncode == 0:
                print(f"Timeline created successfully: {output_file}")
                return output_file
            else:
                print("Error creating timeline")
                return None
                
        except Exception as e:
            print(f"Error creating timeline: {e}")
            return None
    
    def parse_timeline(self, timeline_file):
        """Parse timeline CSV file"""
        
        timeline_data = []
        
        try:
            with open(timeline_file, 'r') as f:
                # Skip header lines
                lines = f.readlines()
                
                for line in lines:
                    if line.strip() and not line.startswith('Date'):
                        parts = line.strip().split(',')
                        
                        if len(parts) >= 5:
                            timeline_entry = {
                                'date': parts[0],
                                'size': parts[1],
                                'type': parts[2],
                                'mode': parts[3],
                                'uid': parts[4],
                                'gid': parts[5] if len(parts) > 5 else '',
                                'meta': parts[6] if len(parts) > 6 else '',
                                'filename': ','.join(parts[7:]) if len(parts) > 7 else ''
                            }
                            timeline_data.append(timeline_entry)
            
            self.timeline_data = timeline_data
            print(f"Parsed {len(timeline_data)} timeline entries")
            return timeline_data
            
        except Exception as e:
            print(f"Error parsing timeline: {e}")
            return []
    
    def analyze_activity_patterns(self):
        """Analyze activity patterns in timeline"""
        
        if not self.timeline_data:
            print("No timeline data available for analysis")
            return {}
        
        # Activity by hour
        hourly_activity = defaultdict(int)
        daily_activity = defaultdict(int)
        file_types = defaultdict(int)
        
        for entry in self.timeline_data:
            try:
                # Parse date
                date_str = entry['date']
                if date_str and date_str != '0':
                    dt = datetime.strptime(date_str.split()[0] + ' ' + date_str.split()[1], '%a %b %d %Y %H:%M:%S')
                    
                    # Count by hour
                    hour_key = dt.strftime('%H:00')
                    hourly_activity[hour_key] += 1
                    
                    # Count by day
                    day_key = dt.strftime('%Y-%m-%d')
                    daily_activity[day_key] += 1
                
                # Count file types
                filename = entry.get('filename', '')
                if '.' in filename:
                    ext = filename.split('.')[-1].lower()
                    file_types[ext] += 1
                    
            except Exception as e:
                continue
        
        analysis = {
            'total_entries': len(self.timeline_data),
            'hourly_activity': dict(hourly_activity),
            'daily_activity': dict(daily_activity),
            'file_types': dict(file_types),
            'peak_hour': max(hourly_activity, key=hourly_activity.get) if hourly_activity else None,
            'peak_day': max(daily_activity, key=daily_activity.get) if daily_activity else None
        }
        
        self.analysis_results = analysis
        return analysis
    
    def find_suspicious_activity(self):
        """Identify potentially suspicious activity"""
        
        suspicious_indicators = []
        
        if not self.timeline_data:
            return suspicious_indicators
        
        # Look for activity during unusual hours (late night/early morning)
        unusual_hours = ['00', '01', '02', '03', '04', '05']
        unusual_activity = 0
        
        for entry in self.timeline_data:
            try:
                date_str = entry['date']
                if date_str and date_str != '0':
                    dt = datetime.strptime(date_str.split()[0] + ' ' + date_str.split()[1], '%a %b %d %Y %H:%M:%S')
                    
                    if dt.strftime('%H') in unusual_hours:
                        unusual_activity += 1
                        
            except:
                continue
        
        if unusual_activity > 10:  # Threshold for suspicious activity
            suspicious_indicators.append({
                'type': 'unusual_hours',
                'description': f'High activity during unusual hours: {unusual_activity} events',
                'severity': 'medium'
            })
        
        # Look for rapid file creation/deletion
        rapid_activity_threshold = 100  # files per minute
        
        # Group by minute
        minute_activity = defaultdict(int)
        for entry in self.timeline_data:
            try:
                date_str = entry['date']
                if date_str and date_str != '0':
                    dt = datetime.strptime(date_str.split()[0] + ' ' + date_str.split()[1], '%a %b %d %Y %H:%M:%S')
                    minute_key = dt.strftime('%Y-%m-%d %H:%M')
                    minute_activity[minute_key] += 1
            except:
                continue
        
        for minute, count in minute_activity.items():
            if count > rapid_activity_threshold:
                suspicious_indicators.append({
                    'type': 'rapid_activity',
                    'description': f'Rapid file activity at {minute}: {count} events',
                    'severity': 'high'
                })
        
        # Look for suspicious file extensions
        suspicious_extensions = ['exe', 'bat', 'cmd', 'scr', 'pif', 'com']
        
        for entry in self.timeline_data:
            filename = entry.get('filename', '').lower()
            for ext in suspicious_extensions:
                if filename.endswith(f'.{ext}'):
                    suspicious_indicators.append({
                        'type': 'suspicious_file',
                        'description': f'Suspicious file: {entry.get("filename", "")}',
                        'severity': 'medium',
                        'timestamp': entry.get('date', ''),
                        'filename': entry.get('filename', '')
                    })
                    break
        
        return suspicious_indicators
    
    def generate_analysis_report(self, output_file='timeline_analysis.json'):
        """Generate comprehensive timeline analysis report"""
        
        # Perform analysis
        patterns = self.analyze_activity_patterns()
        suspicious = self.find_suspicious_activity()
        
        report = {
            'analysis_timestamp': datetime.now().isoformat(),
            'image_file': self.image_path,
            'timeline_statistics': patterns,
            'suspicious_indicators': suspicious,
            'summary': {
                'total_timeline_entries': patterns.get('total_entries', 0),
                'suspicious_events': len(suspicious),
                'peak_activity_hour': patterns.get('peak_hour'),
                'peak_activity_day': patterns.get('peak_day')
            }
        }
        
        # Save report
        with open(output_file, 'w') as f:
            json.dump(report, f, indent=2)
        
        print(f"Timeline analysis report saved: {output_file}")
        
        # Print summary
        print("\nTimeline Analysis Summary:")
        print(f"Total timeline entries: {patterns.get('total_entries', 0)}")
        print(f"Suspicious indicators found: {len(suspicious)}")
        print(f"Peak activity hour: {patterns.get('peak_hour', 'Unknown')}")
        print(f"Peak activity day: {patterns.get('peak_day', 'Unknown')}")
        
        if suspicious:
            print("\nSuspicious Activity Detected:")
            for indicator in suspicious[:5]:  # Show first 5
                print(f"- {indicator['type']}: {indicator['description']}")
        
        return report

# Usage
if __name__ == "__main__":
    image_path = "/evidence/disk_image.dd"
    
    analyzer = TSKTimelineAnalyzer(image_path)
    
    # Create timeline
    timeline_file = analyzer.create_timeline()
    
    if timeline_file:
        # Parse timeline
        analyzer.parse_timeline(timeline_file)
        
        # Generate analysis report
        analyzer.generate_analysis_report()

Integration Examples ​

Autopsy Integration ​

bash
#!/bin/bash
# TSK and Autopsy integration script

IMAGE_PATH="$1"
CASE_NAME="$2"
CASE_DIR="/cases/$CASE_NAME"

if [ -z "$IMAGE_PATH" ] || [ -z "$CASE_NAME" ]; then
    echo "Usage: $0 <image_path> <case_name>"
    exit 1
fi

echo "Creating integrated TSK/Autopsy analysis for: $IMAGE_PATH"

# Create case directory
mkdir -p "$CASE_DIR"

# Step 1: TSK preliminary analysis
echo "Step 1: Running TSK preliminary analysis..."
mmls "$IMAGE_PATH" > "$CASE_DIR/partition_table.txt"
fsstat "$IMAGE_PATH" > "$CASE_DIR/filesystem_info.txt"

# Step 2: Create timeline with TSK
echo "Step 2: Creating timeline with TSK..."
fls -r -m "/" "$IMAGE_PATH" > "$CASE_DIR/timeline.body"
mactime -b "$CASE_DIR/timeline.body" -d > "$CASE_DIR/timeline.csv"

# Step 3: Extract key files with TSK
echo "Step 3: Extracting key files..."
mkdir -p "$CASE_DIR/extracted_files"

# Extract registry files (Windows)
fls "$IMAGE_PATH" | grep -i "system\|software\|sam\|security" | while read line; do
    inode=$(echo "$line" | awk '{print $2}' | cut -d: -f1)
    filename=$(echo "$line" | awk '{print $3}')
    
    if [[ $inode =~ ^[0-9]+$ ]]; then
        icat "$IMAGE_PATH" "$inode" > "$CASE_DIR/extracted_files/$filename"
    fi
done

# Step 4: Import into Autopsy (if available)
if command -v autopsy &> /dev/null; then
    echo "Step 4: Importing into Autopsy..."
    # Autopsy command-line import would go here
    # This depends on Autopsy version and configuration
fi

echo "Integrated analysis completed. Results in: $CASE_DIR"

YARA Integration ​

python
#!/usr/bin/env python3
# TSK and YARA integration for malware detection

import subprocess
import yara
import os
import tempfile

class TSKYaraScanner:
    def __init__(self, image_path, yara_rules_path):
        self.image_path = image_path
        self.yara_rules = yara.compile(yara_rules_path)
        self.matches = []
    
    def scan_files(self, offset='0'):
        """Scan files in disk image with YARA rules"""
        
        # Get file listing
        cmd = ['fls', '-r', '-o', offset, self.image_path]
        result = subprocess.run(cmd, capture_output=True, text=True)
        
        for line in result.stdout.split('\n'):
            if line.strip() and line.startswith('r/r'):
                parts = line.split()
                if len(parts) >= 3:
                    inode = parts[1].split(':')[0]
                    filename = parts[2]
                    
                    # Extract file content
                    try:
                        with tempfile.NamedTemporaryFile() as temp_file:
                            extract_cmd = ['icat', '-o', offset, self.image_path, inode]
                            subprocess.run(extract_cmd, stdout=temp_file, check=True)
                            
                            # Scan with YARA
                            matches = self.yara_rules.match(temp_file.name)
                            
                            if matches:
                                self.matches.append({
                                    'filename': filename,
                                    'inode': inode,
                                    'matches': [str(match) for match in matches]
                                })
                                
                                print(f"YARA match in {filename}: {matches}")
                                
                    except Exception as e:
                        print(f"Error scanning {filename}: {e}")
        
        return self.matches

# Usage
scanner = TSKYaraScanner("/evidence/disk_image.dd", "/rules/malware.yar")
matches = scanner.scan_files()

Troubleshooting ​

Common Issues ​

Image Format Issues:

bash
# Check image format
file disk_image.dd

# Convert image formats
dd if=disk_image.raw of=disk_image.dd bs=512

# Handle E01 images
ewfmount disk_image.E01 /mnt/ewf
# Then use /mnt/ewf/ewf1 as image path

# Handle split images
cat disk_image.001 disk_image.002 > disk_image.dd

Partition Detection Issues:

bash
# Force partition table type
mmls -t dos disk_image.dd
mmls -t gpt disk_image.dd

# Manual offset calculation
fdisk -l disk_image.dd

# Check for damaged partition table
testdisk disk_image.dd

# Use hexdump to examine boot sector
hexdump -C disk_image.dd | head -20

File System Issues:

bash
# Check file system type
fsstat disk_image.dd

# Force file system type
fls -f ntfs disk_image.dd
fls -f ext3 disk_image.dd

# Check for file system damage
fsck.ext4 -n disk_image.dd

# Use alternative tools
debugfs disk_image.dd

Debugging ​

Enable detailed debugging and error reporting:

bash
# Verbose output
fls -v disk_image.dd

# Debug mode (if available)
TSK_DEBUG=1 fls disk_image.dd

# Check TSK version and capabilities
mmls -V
fls -V

# Monitor system calls
strace fls disk_image.dd

# Check for library dependencies
ldd $(which fls)

Security Considerations ​

Evidence Integrity ​

Write Protection:

  • Always work with read-only copies of evidence
  • Use hardware write blockers when possible
  • Verify image integrity with cryptographic hashes
  • Document all analysis procedures
  • Maintain chain of custody records

Hash Verification:

bash
# Calculate image hash before analysis
md5sum disk_image.dd > disk_image.md5
sha256sum disk_image.dd > disk_image.sha256

# Verify hash after analysis
md5sum -c disk_image.md5
sha256sum -c disk_image.sha256

Documentation Requirements:

  • Maintain detailed logs of all TSK commands executed
  • Document analysis methodology and procedures
  • Record all findings and their significance
  • Preserve original evidence and analysis results
  • Follow applicable legal and regulatory requirements

Best Practices:

  • Use standardized forensic procedures
  • Validate tools and techniques regularly
  • Maintain current knowledge of legal requirements
  • Implement quality assurance processes
  • Regular training and certification updates

References ​

  1. The Sleuth Kit Official Website
  2. TSK Documentation and Wiki
  3. Digital Forensics with The Sleuth Kit
  4. File System Forensic Analysis
  5. NIST Computer Forensics Tool Testing