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Lack of protection against deletion

Need​

Implementation of safeguards against accidental deletion

Context​

  • Usage of Java 8 for developing applications with enhanced features and performance
  • Usage of javax.servlet-api for building Java web applications with Servlets

Description​

Non compliant code​

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class VulnerableServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response) {
        String id = request.getParameter("id");
        deleteObject(id);
    }

    private void deleteObject(String id) {
        // Assume this function deletes an object from database
    }
}

In the above code, the doGet method of the VulnerableServlet class takes in a request and retrieves a parameter 'id' from it. This 'id' is then passed on to the deleteObject method which, for the sake of this example, we assume deletes an object with the corresponding 'id' from the database.

The vulnerability here lies in the fact that there is no protection against deletion. Any user who is able to send a GET request to this servlet can delete objects just by knowing their 'id'. This could result in critical data loss if a user accidentally or intentionally deletes important objects.

There are no checks to verify the identity of the user or to confirm the deletion operation, making it a critical vulnerability. This lack of protection against deletion is a serious security risk as it can lead to unauthorized data manipulation or loss.

Steps​

  • Implement authentication and authorization mechanisms to ensure that only authorized users can access the delete functionality.
  • Add a confirmation step before deleting the object to prevent accidental deletions.
  • Implement access control mechanisms to restrict the deletion of critical objects to specific roles or users.
  • Implement logging and auditing mechanisms to track delete operations and identify any unauthorized or suspicious activities.
  • Consider implementing a soft delete mechanism instead of permanently deleting objects, allowing for easier recovery if needed.

Compliant code​

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class SecureServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response) {
        String id = request.getParameter("id");
        String userRole = getUserRole(request); // Assume this function gets the role of the current user

        if (isAuthorized(userRole)) {
            boolean confirmed = getConfirmation(request); // Assume this function gets a confirmation from the user
            if (confirmed) {
                softDeleteObject(id); // Assume this function marks an object as deleted instead of permanently deleting it
                logDeletion(id, request); // Assume this function logs the deletion
            }
        }
    }

    private boolean isAuthorized(String userRole) {
        // Check if the user role is authorized to delete objects
        // This is just a placeholder, actual implementation will depend on your authorization logic
        return userRole.equals("admin");
    }

    private boolean getConfirmation(HttpServletRequest request) {
        // Get confirmation from the user
        // This is just a placeholder, actual implementation will depend on your confirmation logic
        return request.getParameter("confirm").equals("yes");
    }

    private void softDeleteObject(String id) {
        // Mark the object as deleted instead of permanently deleting it
        // This is just a placeholder, actual implementation will depend on your deletion logic
    }

    private void logDeletion(String id, HttpServletRequest request) {
        // Log the deletion
        // This is just a placeholder, actual implementation will depend on your logging logic
    }
}

The updated code includes several measures to protect against accidental deletion of critical objects:

  1. Authentication and Authorization: The isAuthorized function checks if the user role is authorized to delete objects. This ensures that only authorized users can access the delete functionality.

  2. Confirmation Step: The getConfirmation function gets a confirmation from the user before deleting the object. This prevents accidental deletions.

  3. Soft Deletion: The softDeleteObject function marks an object as deleted instead of permanently deleting it. This allows for easier recovery if needed.

  4. Logging and Auditing: The logDeletion function logs the deletion, including the ID of the deleted object and the request details. This allows for tracking of delete operations and identification of any unauthorized or suspicious activities.

Please note that the actual implementation of these functions will depend on your specific requirements and system architecture. The provided code is a general template and may need to be adjusted to fit your needs.

References​

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