Skip to main content

Sensitive information sent insecurely

Need​

Secure transmission of sensitive information

Context​

  • Usage of Java for building robust and scalable applications
  • Usage of javax.servlet for building Java web applications with Servlet technology
  • Usage of java.io for input and output operations in Java

Description​

Non compliant code​

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;

public class SensitiveInfoServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String sensitiveInfo = "This is some sensitive information.";

        PrintWriter out = response.getWriter();
        out.println(sensitiveInfo);
    }
}

The above code is a simple servlet that sends some sensitive information as a response to a GET request. This is done by getting a PrintWriter from the HttpServletResponse object and then calling the println method on it with the sensitive information as argument.

This is insecure because the information is sent over an unencrypted HTTP connection, which means it could be intercepted and read by anyone who is able to listen in on the network traffic. This could potentially include attackers who are on the same network or who are able to position themselves between the server and the client (a man-in-the-middle attack).

Furthermore, the information is sent as plain text, which means it is not obfuscated or encrypted in any way. This makes it very easy for an attacker who intercepts the information to understand and misuse it.

The integrity of the information is also not protected, which means an attacker could potentially alter the information in transit without the server or the client being able to detect this.

In summary, the code is vulnerable because it sends sensitive information insecurely, without any measures to protect its confidentiality or integrity.

Steps​

  • Use a secure channel or method to send sensitive information
  • Encrypt the sensitive information before sending it
  • Implement secure communication protocols such as HTTPS
  • Ensure the server and client have proper authentication and authorization mechanisms
  • Implement access controls to restrict access to sensitive information
  • Regularly update and patch the system to fix any security vulnerabilities

Compliant code​

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.util.Base64;
import java.security.Key;

public class SensitiveInfoServlet extends HttpServlet {

    private static String algorithm = "AES";
    private static byte[] keyValue = new byte[]{'A', 'S', 'e', 'c', 'r', 'e', 't', 'K', 'e', 'y', '1', '2', '3', '4', '5', '6'};

    // Method to encrypt the sensitive information
    private static String encrypt(String sensitiveInfo) throws Exception {
        Key key = generateKey();
        Cipher c = Cipher.getInstance(algorithm);
        c.init(Cipher.ENCRYPT_MODE, key);
        byte[] encValue = c.doFinal(sensitiveInfo.getBytes());
        String encryptedValue = Base64.getEncoder().encodeToString(encValue);
        return encryptedValue;
    }

    // Method to generate a secret key
    private static Key generateKey() throws Exception {
        Key key = new SecretKeySpec(keyValue, algorithm);
        return key;
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String sensitiveInfo = "This is some sensitive information.";

        try {
            String encryptedSensitiveInfo = encrypt(sensitiveInfo);
            PrintWriter out = response.getWriter();
            out.println(encryptedSensitiveInfo);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

The above code fixes the vulnerability by encrypting the sensitive information before sending it. The encryption is done using the AES (Advanced Encryption Standard) algorithm. A secret key is generated and used for the encryption. The sensitive information is then encrypted using this key and the AES algorithm. The encrypted information is then sent to the client.

This ensures that even if the information is intercepted during transmission, it cannot be understood without the decryption key. This greatly enhances the security of the sensitive information.

Please note that this is a basic example and in a real-world scenario, you would need to secure the key used for encryption and it should not be hardcoded as in this example. Also, you should use HTTPS for communication to ensure the integrity and confidentiality of the transmitted data.

Furthermore, proper authentication and authorization mechanisms should be implemented to ensure that only authorized users have access to the sensitive information. Regular updates and patches should also be applied to the system to fix any security vulnerabilities.

References​

Last updated on