Need

Prevention of unauthorized access to files and functionalities

Context

Description

import 'package:shelf/shelf.dart' as shelf;
import 'package:shelf_router/shelf_router.dart';

class UserController {
  Router _router;

  UserController() {
    _router.post('/update', _updateUserData);...

In the above code, the `_updateUserData` method in the `UserController` class is vulnerable. This method is responsible for updating user data and is exposed as a POST endpoint at `/update`. The vulnerability lies in the fact that the method directly uses user-provided data without any validation or sanitization. The user data is read from the request and passed directly to the `updateUser` method. This opens up a potential attack vector where a malicious user can inject harmful characters or scripts into the user data. Since the application does not validate or sanitize the user input, it processes the harmful input as is. This can lead to inappropriate behavior in the application, such as unauthorized access to files. In the worst-case scenario, this vulnerability could be exploited to gain unauthorized access to SharePoint and other functionalities, leading to a potential data breach. Therefore, it is critical to fix this vulnerability by adding appropriate input validation and sanitization.

import 'package:shelf/shelf.dart' as shelf;
import 'package:shelf_router/shelf_router.dart';

class UserController {
  Router _router;

  UserController() {
    _router.post('/update', _updateUserData);...

The updated code now includes input validation and sanitization to prevent unauthorized access to files. The `isValid` function is used to validate the user input. It checks if the user ID and update data are in the expected format and do not contain any special characters. If the validation fails, the function returns a 403 Forbidden response. The `sanitize` function is used to sanitize the user input. It removes any potentially harmful characters from the user input. This prevents any code injection attacks. The `updateUser` function now uses a parameterized query to update the user data. This ensures that the user input is always treated as a literal value and not part of the SQL command. The application now follows the principle of least privilege. It only has the necessary permissions for its functionality. This minimizes the potential damage in case of a security breach. The application also implements access controls to ensure that only authorized users can access certain functionalities and files. This prevents unauthorized access to files.

References