How to Build an Antivirus App on Mobile Using Python (Step-by-Step Guide)

 

Creating an Antivirus Application using Python directly on your mobile phone is an advanced and rewarding project. This guide explains the process in detail, focusing on building a malware scanner that checks for suspicious files and behaviors.

1. Setting Up the Development Environment

Step 1: Install Python IDE on Mobile

1. Download Pydroid 3 from the Google Play Store.

2. Allow necessary permissions for file access.

Step 2: Install Required Libraries

Open the Pydroid 3 Terminal and install the following libraries:

pip install pyfiglet

pip install hashlib

pip install os-sys

pyfiglet – For text banners (optional).

hashlib – To generate file hashes for scanning.

os and sys – To access files and directories.

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2. Designing the Antivirus Application

Step 1: Create a New File

Open Pydroid 3 and create a file called antivirus_app.py.

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3. Writing the Core Code

Step 1: Import Required Modules

import os

import hashlib

import time

Step 2: Define Malware Signatures

# Predefined hash signatures for malicious files

malware_signatures = [

    "5d41402abc4b2a76b9719d911017c592", # Example malware hash

    "7d793037a0760186574b0282f2f435e7" # Example malware hash

]

Step 3: Scan Files for Malware

def scan_file(file_path):

    try:

        # Calculate the MD5 hash of the file

        with open(file_path, "rb") as file:

            file_hash = hashlib.md5(file.read()).hexdigest()

        # Check if the hash matches any malware signature

        if file_hash in malware_signatures:

            return True # Malware detected

        return False # Safe file

    except Exception as e:

        return False # Skip files that cannot be scanned

Step 4: Scan a Directory

def scan_directory(directory):

    infected_files = []

    total_files = 0

    for root, dirs, files in os.walk(directory):

        for file in files:

            total_files += 1

            file_path = os.path.join(root, file)

            if scan_file(file_path):

                infected_files.append(file_path)

    return infected_files, total_files

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4. Building the User Interface

Step 1: Display Menu Options

def display_menu():

    print("\n--- Antivirus App ---")

    print("1. Scan Device")

    print("2. Exit")

Step 2: Main Application Logic

def main():

    while True:

        display_menu()

        choice = input("Enter your choice (1/2): ")

        if choice == '1':

            directory = input("Enter the directory to scan (e.g., /storage/emulated/0/): ")

            print("Scanning, please wait...")

            infected_files, total_files = scan_directory(directory)

            print(f"\nScan completed! Total files scanned: {total_files}")

            if infected_files:

                print(f"Warning! {len(infected_files)} infected files found:")

                for file in infected_files:

                    print(f"- {file}")

            else:

                print("No infected files found. Your device is safe!")

        elif choice == '2':

            print("Exiting Antivirus App. Goodbye!")

            break

        else:

            print("Invalid choice. Please try again.")

Step 3: Run the Application

if __name__ == "__main__":

    main()

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5. Running the Antivirus App

Step 1: Save and Execute

1. Save the code in Pydroid 3.

2. Click Run to execute the script.

Step 2: Test the Application

Provide the directory path where you want to scan files.

The app will analyze files and check for malware signatures.

6. Enhancing the Application

Feature Ideas:

1. Real-Time Protection:

Monitor file changes and scan new files automatically.

2. Update Malware Database:

Download new signatures from an online database.

3. Quarantine Infected Files:

Move infected files to a secure folder.

4. Notifications and Logs:

Save scan reports and send notifications.

5. User-Friendly Interface:

Integrate with Kivy or Tkinter to add graphical interfaces.

7. Example: Quarantine Feature

def quarantine_file(file_path):

    quarantine_dir = "quarantine"

    if not os.path.exists(quarantine_dir):

        os.makedirs(quarantine_dir)

    os.rename(file_path, os.path.join(quarantine_dir, os.path.basename(file_path)))

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8. Deploying the App

Option 1: Convert to APK

1. Use Buildozer or Kivy framework.

2. Package the app as an APK for Android.

Option 2: Share Python Script

Share the Python file to allow others to run it using Pydroid 3 or similar IDEs.

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9. Conclusion

Congratulations! You’ve built a basic antivirus application that can scan directories for suspicious files based on hash signatures. While this app is a foundation, you can enhance it further with features like real-time scanning, automatic updates, and graphical user interfaces.

Next Steps:

Add new features to make it more powerful.

Deploy the app on Android devices as a standalone APK.

Continue learning about cybersecurity and malware analysis!