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Insecure object reference - Data

Need​

Secure object reference validation and authorization

Context​

  • Usage of Java for building cross-platform applications and enterprise-level software
  • Usage of javax.servlet for building Java web applications
  • 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 StoreDataServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        
        String storeId = request.getParameter("storeId");
        String memberId = request.getParameter("memberId");

        Store store = StoreService.getStore(storeId);
        Member member = MemberService.getMember(memberId);

        if (store != null && member != null) {
            request.setAttribute("store", store);
            request.setAttribute("member", member);
            request.getRequestDispatcher("/storeData.jsp").forward(request, response);
        } else {
            response.sendError(HttpServletResponse.SC_NOT_FOUND);
        }
    }
}

The code snippet above is a servlet that handles GET requests to fetch and display store and member data.

The servlet retrieves the store and member identifiers from the request parameters and uses these to fetch the corresponding store and member objects from the respective services. These objects are then set as attributes in the request and forwarded to a JSP page for display.

The vulnerability lies in the fact that there are no checks to ensure that the user making the request has the necessary permissions to view the requested store or member data. As a result, any user who knows the identifiers of a store or member can view their data, even if they are not assigned to that store or are not that member.

This is an example of an Insecure Direct Object Reference (IDOR) vulnerability, where the application exposes a reference to an internal implementation object, such as a file, directory, or database key without any access control checks or other protection, allowing attackers to manipulate these references to access unauthorized data.

Steps​

  • Implement proper authorization and access control mechanisms to ensure that users can only access data that they are authorized to.
  • Validate the user's permissions before allowing access to sensitive data.
  • Use session management to track and validate user sessions.
  • Implement proper input validation and sanitization to prevent malicious input.
  • Ensure that the store and member identifiers are properly validated and authorized before retrieving the corresponding data.
  • Consider implementing a role-based access control system to manage user permissions.
  • Regularly review and update the access control mechanisms to address any new vulnerabilities or changes in the application.
  • Conduct security testing and code reviews to identify and fix any other potential vulnerabilities.

Compliant code​

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

public class StoreDataServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        
        HttpSession session = request.getSession();
        User user = (User) session.getAttribute("user");

        String storeId = request.getParameter("storeId");
        String memberId = request.getParameter("memberId");

        // Validate the storeId and memberId
        if (!isValid(storeId) || !isValid(memberId)) {
            response.sendError(HttpServletResponse.SC_BAD_REQUEST);
            return;
        }

        // Check if the user has the necessary permissions to access the store and member data
        if (!UserService.hasPermission(user, storeId, memberId)) {
            response.sendError(HttpServletResponse.SC_FORBIDDEN);
            return;
        }

        Store store = StoreService.getStore(storeId);
        Member member = MemberService.getMember(memberId);

        if (store != null && member != null) {
            request.setAttribute("store", store);
            request.setAttribute("store", member);
            request.getRequestDispatcher("/storeData.jsp").forward(request, response);
        } else {
            response.sendError(HttpServletResponse.SC_NOT_FOUND);
        }
    }

    private boolean isValid(String id) {
        // Implement validation logic here
        return true;
    }
}

The updated code includes several security measures to prevent insecure object reference vulnerabilities.

Firstly, the code retrieves the current user from the session. This user object is then used to check if the user has the necessary permissions to access the requested store and member data. This is done using a hypothetical UserService.hasPermission(user, storeId, memberId) method, which should be implemented to check the user's permissions.

Before checking the user's permissions, the code validates the storeId and memberId parameters to ensure they are valid. This is done using a hypothetical isValid(id) method, which should be implemented to validate the identifiers.

If the identifiers are not valid or the user does not have the necessary permissions, the code sends an error response and returns, preventing any further processing.

If the identifiers are valid and the user has the necessary permissions, the code retrieves the corresponding store and member data and forwards the request to the storeData.jsp page.

This approach ensures that users can only access data they are authorized to, preventing insecure object reference vulnerabilities.

References​

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