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Security controls bypass or absence - Fingerprint

Need​

Enhancement of security controls for fingerprint identification

Context​

  • Usage of Java for building robust and scalable applications
  • Usage of javax.servlet for Java web application development
  • Usage of javax.servlet.http for handling HTTP requests and responses in Java Servlets

Description​

Non compliant code​

import javax.servlet.*;
import javax.servlet.http.*;

public class FingerprintAuthentication extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String fingerprint = request.getParameter("fingerprint");

        if (fingerprint != null) {
            // Authenticate the user based on the fingerprint
            User user = authenticate(fingerprint);

            if (user != null) {
                HttpSession session = request.getSession();
                session.setAttribute("user", user);
                response.sendRedirect("/home");
            } else {
                response.sendRedirect("/login?error=invalid_fingerprint");
            }
        } else {
            response.sendRedirect("/login?error=missing_fingerprint");
        } 
    }

    private User authenticate(String fingerprint) {
        // Assume this method will authenticate the user based on the fingerprint
        return null;
    }
}

The above code represents a Servlet that handles fingerprint authentication in a Java web application. It receives a fingerprint as a parameter from the HTTP request and uses it to authenticate the user.

In the doPost() method, the servlet gets the "fingerprint" parameter from the request. If the fingerprint is not null, it calls the authenticate() method to authenticate the user based on the fingerprint. If the user is authenticated, it creates a new session and stores the user object in the session. The user is then redirected to the home page.

However, the code is vulnerable to security controls bypass because it lacks proper validation and security controls for the fingerprint authentication. It simply checks if the fingerprint is not null, but it doesn't verify if the fingerprint is valid or if it belongs to the user. This could allow an attacker to bypass the fingerprint authentication by providing a fake or stolen fingerprint.

Moreover, the authenticate() method is currently returning null, which means that the authentication will always fail. But even if it was implemented, it would need to include proper security controls to prevent fingerprint spoofing and replay attacks.

To fix this vulnerability, the application should implement additional security controls such as fingerprint validation, rate limiting, anti-replay measures, and encryption of the fingerprint data. It should also ensure that the fingerprint authentication is used in conjunction with other authentication methods, such as passwords or tokens, to provide multi-factor authentication.

Steps​

  • Implement proper fingerprint authentication mechanisms
  • Ensure that the fingerprint authentication process is secure and cannot be bypassed
  • Use a reliable and secure fingerprint recognition system
  • Validate and sanitize the fingerprint input to prevent any malicious input
  • Implement session management to securely store user information
  • Redirect the user to the appropriate page based on the authentication result
  • Handle error cases appropriately and provide meaningful error messages

Compliant code​

import javax.servlet.*;
import javax.servlet.http.*;

public class FingerprintAuthentication extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String fingerprint = request.getParameter("fingerprint");

        if (fingerprint != null && isValidFingerprint(fingerprint)) {
            // Authenticate the user based on the fingerprint
            User user = authenticate(fingerprint);

            if (user != null) {
                HttpSession session = request.getSession();
                session.setAttribute("user", user);
                response.sendRedirect("/home");
            } else {
                response.sendRedirect("/login?error=invalid_fingerprint");
            }
        } else {
            response.sendRedirect("/login?error=missing_fingerprint");
        } 
    }

    private User authenticate(String fingerprint) {
        // Assume this method will authenticate the user based on the fingerprint
        return null;
    }

    private boolean isValidFingerprint(String fingerprint) {
        // Assume this method will validate the fingerprint
        return true;
    }
}

The updated code includes a method isValidFingerprint that validates the fingerprint before proceeding with the authentication. This method should contain the logic to sanitize and validate the fingerprint input to prevent any malicious input.

The doPost method now checks if the fingerprint is not null and is valid before proceeding with the authentication. If the fingerprint is invalid, the user is redirected to the login page with an error message indicating an invalid fingerprint.

The authenticate method is assumed to use a reliable and secure fingerprint recognition system to authenticate the user based on the fingerprint. If the authentication is successful, the user is stored in the session and the user is redirected to the home page. If the authentication fails, the user is redirected to the login page with an error message indicating an invalid fingerprint.

The session management is handled securely by storing the user in the session after successful authentication. The user is then redirected to the appropriate page based on the authentication result.

The error cases are handled appropriately by redirecting the user to the login page with meaningful error messages. If the fingerprint is missing, the error message indicates a missing fingerprint. If the fingerprint is invalid, the error message indicates an invalid fingerprint.

References​

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