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Insufficient data authenticity validation

Need​

Enhanced data authenticity validation and verification

Context​

  • Usage of TypeScript for statically typed JavaScript development
  • Usage of Express for building web applications and APIs

Description​

Non compliant code​

import express from 'express';

const app = express();
app.use(express.json());

app.post('/updateName', (req, res) => {
  const { name } = req.body;

  // Insecure code: No server-side validation of the name field
  // Allows non-existing names to be used
  // Potential for injection of malicious characters
  // into the application fields

  // Update the name in the database
  // ...

  res.status(200).json({ message: 'Name updated successfully' });
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

The vulnerability in this code is an insufficient data authenticity validation. In the app.post('/updateName') route, the code receives a request with a JSON payload containing a name field. However, there is no server-side validation of the name field, allowing any value to be accepted, including non-existing names or potentially malicious characters.

This lack of validation opens up the possibility for an attacker to inject invalid or malicious data into the name field. For example, an attacker could send a request with a name that contains special characters or SQL injection payloads, potentially leading to security vulnerabilities or data corruption in the application.

To mitigate this vulnerability, it is recommended to implement server-side validation of the data entered into different types of fields in the application. This validation should ensure that the data is of the expected type, format, and meets any other specific requirements. By validating the data on the server side, the application can prevent the use of invalid or malicious data and enhance the overall security of the system.

Steps​

  • Implement server-side validation for the 'name' field in the '/updateName' route handler
  • Validate the 'name' field to ensure it meets the required criteria (e.g., length, allowed characters)
  • If the 'name' field is invalid, return an appropriate error response to the client
  • Only update the name in the database if the 'name' field passes the validation
  • Consider using a validation library or framework to simplify the validation process
  • Test the updated code to ensure it properly validates the 'name' field

Compliant code​

import express from 'express';
import { body, validationResult } from 'express-validator';

const app = express();
app.use(express.json());

app.post('/updateName', [
  body('name').isLength({ min: 1 }).withMessage('Name is required'),
  // Add more validation rules as needed
], (req, res) => {
  const errors = validationResult(req);
  if (!errors.isEmpty()) {
    return res.status(400).json({ errors: errors.array() });
  }

  const { name } = req.body;

  // Update the name in the database
  // ...

  res.status(200).json({ message: 'Name updated successfully' });
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

The fixed code addresses the vulnerability by implementing server-side validation for the data entered into different fields of the application.

  1. The code imports the necessary modules from the Express framework, including the body and validationResult functions from the express-validator package.

  2. The Express application is created using express() and the express.json() middleware is used to parse incoming JSON data.

  3. The code defines a POST route '/updateName' to handle updating the name field. It uses the body function from express-validator to define validation rules for the 'name' field. In this case, it checks if the length of the name is at least 1 character.

  4. Inside the route handler, the validationResult function is used to check if there are any validation errors based on the defined rules. If there are errors, a 400 response is sent back to the client along with the error messages.

  5. If there are no validation errors, the code extracts the 'name' field from the request body.

  6. The code then proceeds to update the name in the database (not shown in the code snippet).

  7. Finally, a 200 response is sent back to the client indicating that the name has been updated successfully.

By implementing server-side validation using the express-validator package, the fixed code ensures that only valid and authentic data is accepted for the 'name' field, mitigating the vulnerability of allowing potentially malicious characters to be injected into the application.

References​

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