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Lack of data validation - URL

Need​

Implementation of proper data validation and sanitization for URL parameters

Context​

  • Usage of PHP 7.0+ for server-side scripting and web development
  • Usage of Request for making HTTP requests in Node.js
  • Usage of the Document library for manipulating and working with HTML documents

Description​

Non compliant code​

public function getDocumentsByDate(Request $request) {
    $date = $request->get('date');
    $documents = Document::where('date', $date)->get();
    return response()->json($documents);
}

This code snippet is a function inside a controller that handles a request to get all documents sent on a specific date. The date is passed as a parameter in the URL and is fetched using $request->get('date');.

The vulnerability lies in the lack of data validation. The date parameter is not validated before it is used in the query to fetch documents from the database. This means that any user on the Internet can obtain information on users who have sent their documents through the portal by sending as a parameter in the URL the date on which the document was sent.

This lack of data validation could potentially lead to unauthorized access to sensitive user data, and could also open up the possibility of SQL injection attacks if the raw input is used in constructing SQL queries.

Steps​

  • Add authentication to the function to ensure only authorized users can access the data.
  • Implement input validation to ensure the 'date' parameter is in the correct format and within acceptable ranges.
  • Implement rate limiting to prevent brute force attacks.
  • Consider using a more secure method to retrieve documents, such as using unique, non-guessable IDs instead of dates.
  • Encrypt sensitive data in transit and at rest to prevent unauthorized access.

Compliant code​

public function getDocumentsByDate(Request $request) {
    // Add authentication
    $this->middleware('auth');

    // Validate the 'date' input
    $validatedData = $request->validate([
        'date' => 'required|date',
    ]);

    $date = $validatedData['date'];

    // Implement rate limiting
    if (Cache::get($date)) {
        return response()->json(['message' => 'Too many requests'], 429);
    }

    Cache::put($date, true, 60);

    $documents = Document::where('date', $date)->get();

    // Encrypt the data
    $encryptedDocuments = encrypt($documents);

    return response()->json($encryptedDocuments);
}

The updated code includes several security measures to fix the vulnerability:

  1. Authentication: The middleware('auth') function ensures that only authenticated users can access the function.

  2. Input Validation: The validate function checks that the 'date' parameter is present and is a valid date. This prevents SQL injection attacks and ensures the function behaves as expected.

  3. Rate Limiting: The Cache::get and Cache::put functions are used to implement rate limiting. If a request is made with the same 'date' parameter within a 60 second period, the function will return a 429 'Too Many Requests' response. This prevents brute force attacks.

  4. Data Encryption: The encrypt function is used to encrypt the documents before they are returned in the response. This ensures that even if the data is intercepted in transit, it cannot be read without the encryption key.

References​

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