Skip to main content

Security controls bypass or absence - Fingerprint

Need​

Enhancement of security controls for fingerprint identification

Context​

  • Usage of PHP 7.0 for server-side scripting and web development
  • Usage of Request for making HTTP requests
  • Usage of the Customer package for managing customer data and interactions
  • Usage of Auth for implementing authentication and authorization functionality

Description​

Non compliant code​

public function authenticate(Request $request)
{
    $customer = Customer::where('fingerprint', $request->fingerprint)->first();

    if($customer){
        Auth::login($customer);
        return redirect()->intended('dashboard');
    }
    else{
        return redirect()->back()->withErrors(['fingerprint' => 'Fingerprint not found.']);
    }
}

The above code is a part of a Laravel application which is used for authenticating a user based on their fingerprint. This is a vulnerable piece of code because it does not include any additional security measures to verify the authenticity of the fingerprint.

Here is how the code works:

  1. The function authenticate(Request $request) is called when a user tries to login.
  2. The fingerprint from the request is used to find a customer with the same fingerprint in the database: Customer::where('fingerprint', $request->fingerprint)->first();.
  3. If a customer with the same fingerprint is found, the user is logged in and redirected to the dashboard: Auth::login($customer); return redirect()->intended('dashboard');.
  4. If no customer is found with the same fingerprint, the user is redirected back with an error message: return redirect()->back()->withErrors(['fingerprint' => 'Fingerprint not found.']);.

The vulnerability lies in the fact that there is no additional security measure to verify the authenticity of the fingerprint. A malicious user could potentially bypass this security control by using a stolen or spoofed fingerprint to gain unauthorized access to another user's account.

Steps​

  • Implement multi-factor authentication. This could be a combination of something the user knows (like a password), something the user has (like a mobile device), and something the user is (like a fingerprint).
  • Add a rate limiting mechanism to prevent brute force attacks. This will limit the number of authentication attempts from a single IP address within a certain time period.
  • Encrypt the fingerprint data stored in the database. This will prevent unauthorized access to the fingerprint data even if the database is compromised.
  • Use secure communication protocols like HTTPS to prevent man-in-the-middle attacks.
  • Implement a session timeout mechanism. This will automatically log out the user after a certain period of inactivity.
  • Regularly update and patch the system to fix any known vulnerabilities.

Compliant code​

public function authenticate(Request $request)
{
    // Rate limiting
    if (Cache::has('login_attempts_' . $request->ip())) {
        $loginAttempts = Cache::get('login_attempts_' . $request->ip());
        if ($loginAttempts > 5) {
            return redirect()->back()->withErrors(['fingerprint' => 'Too many login attempts. Please try again later.']);
        }
    }

    $customer = Customer::where('fingerprint', hash('sha256', $request->fingerprint))->first();

    if($customer){
        // Multi-factor authentication
        if (Hash::check($request->password, $customer->password)) {
            Auth::login($customer);
            // Session timeout
            session(['last_activity' => time()]);
            return redirect()->intended('dashboard');
        }
    }

    Cache::increment('login_attempts_' . $request->ip());
    return redirect()->back()->withErrors(['fingerprint' => 'Fingerprint not found.']);
}

The updated code includes several security enhancements to address the vulnerability:

  1. Rate Limiting: The code checks if there have been more than 5 login attempts from the same IP address. If so, it returns an error message and does not proceed with the authentication process. This is done using Laravel's Cache facade.

  2. Multi-factor Authentication: In addition to the fingerprint, the user is also required to enter a password. The entered password is hashed and compared with the hashed password stored in the database. If they match, the user is authenticated.

  3. Fingerprint Encryption: The fingerprint data is hashed using the SHA-256 algorithm before it is compared with the data in the database. This ensures that even if the database is compromised, the actual fingerprint data will not be exposed.

  4. Session Timeout: A timestamp of the last activity is stored in the session data. This can be used to automatically log out the user after a certain period of inactivity.

Remember to use secure communication protocols like HTTPS to prevent man-in-the-middle attacks and regularly update and patch the system to fix any known vulnerabilities.

References​

Last updated on