To create a metadata scraper for digital forensics, we will use the Python programming language and its built-in libraries for metadata extraction. The scraper will be able to work on all types of files, including images, documents, audio, and video.
Step 1: Install Required Libraries To begin, we need to install two Python libraries: ExifRead and PyPDF2. ExifRead is a library for reading metadata from image files, while PyPDF2 is used for reading metadata from PDF documents.
To install these libraries, open a terminal window and enter the following commands:
pip install ExifRead
pip install PyPDF2
Step 2: Import Required Libraries Once the libraries are installed, we need to import them in our Python script. Open your preferred Python editor and create a new script. Then, add the following lines at the top of the file:
import os
import exifread
import PyPDF2
Step 3: Define Metadata Scraper Function Next, we will define a function that will extract metadata from any given file. This function will take the file path as an argument and return a dictionary containing the metadata. Here’s the code for the function:
def extract_metadata(filepath):
# Get file extension
ext = os.path.splitext(filepath)[1].lower()
# Initialize metadata dictionary
metadata = {}
# Extract metadata based on file type
if ext == ".jpg" or ext == ".jpeg" or ext == ".png" or ext == ".gif":
with open(filepath, "rb") as f:
tags = exifread.process_file(f)
for tag in tags.keys():
if tag not in ('JPEGThumbnail', 'TIFFThumbnail', 'Filename', 'EXIF MakerNote'):
metadata[tag] = str(tags[tag])
elif ext == ".pdf":
with open(filepath, "rb") as f:
pdf = PyPDF2.PdfFileReader(f)
info = pdf.getDocumentInfo()
for key, value in info.items():
metadata[key] = value
else:
# Handle unsupported file types
print("Unsupported file type:", ext)
return metadata
In this function, we first get the file extension using the os.path.splitext() function. We then initialize an empty dictionary to hold the metadata. Next, we check the file extension to determine the type of metadata extraction to perform. For image files, we use the ExifRead library to extract the metadata, and for PDF files, we use the PyPDF2 library. If the file type is not supported, we print a message indicating so.
Step 4: Test the Metadata Scraper Now that we have defined our metadata scraper function, we can test it by calling it with the path to a file. Here’s an example:
metadata = extract_metadata("path/to/your/file")
print(metadata)
Replace “path/to/your/file” with the actual file path. When you run this code, you should see a dictionary containing the metadata for the file.
Step 5: Use the Metadata Scraper in Your Digital Forensics Workflows Now that we have a working metadata scraper, we can use it in our digital forensics workflows. You can write a script that iterates over a directory of files, extracts the metadata for each file using the extract_metadata() function, and stores the metadata in a database or other data store for analysis.
The data that the metadata scraper will extract depends on the file type. Here’s are a couple of examples of what the script might output:
For image files (.jpg, .jpeg, .png, .gif), the metadata scraper will extract the following data:
Image size (height and width)
Image resolution
Date and time the image was created or modified
Camera make and model (if available)
Exposure time, aperture, and ISO (if available)
GPS coordinates (if available)
Image orientation
Image format (e.g., JPEG, PNG)
For PDF documents (.pdf), the metadata scraper will extract the following data:
Author of the document
Title of the document
Subject of the document
Number of pages in the document
Date the document was created or modified
Producer of the PDF document
Keywords associated with the document
Encrypted status of the document
Document version
Fonts used in the document
It’s important to note that not all files will contain metadata or the same types of metadata. Some files may contain more or less metadata depending on how they were created or modified. The metadata scraper will extract all available metadata for each file type, but the exact data extracted will vary depending on the file.
That’s it! With these five steps, you now have a working metadata scraper that can extract metadata from all types of files. I hope you found this useful! 