Security controls bypass or absence

Need

Implementation of robust and effective security controls

Context

• Usage of PHP 7.0 for server-side scripting and web development
• Usage of Illuminate\Http\Request for handling HTTP requests in Laravel
• Usage of the User module in the App namespace

Description

Non compliant code

<?php

namespace App\\Http\\Controllers;

use Illuminate\\Http\\Request;
use App\\User;

class UserController extends Controller
{
    public function updateUser(Request $request, $id)
    {
        $user = User::find($id);

        $user->name = $request->input('name');
        $user->email = $request->input('email');

        $user->save();

        return response()->json(['message' => 'User updated successfully']);
    }
}

In the above code, we have a UserController with a method updateUser(). This method is used to update user information. The problem here is that there are no security controls in place to verify if the user making the request has the necessary permissions to update the user information.

This means that any user who knows the endpoint and the user id can make a request to update the user information. This is a serious security flaw as it allows unauthorized users to potentially change sensitive user information.

The vulnerability lies in the absence of authorization checks before performing the update operation. This allows for a security controls bypass, as any user, regardless of their permissions, can update user information.

Steps

• Implement authentication to ensure that only authorized users can update user details.
• Implement authorization to ensure that a user can only update their own details, not those of other users.
• Validate the input data to ensure that it is in the correct format and does not contain malicious content.
• Use prepared statements or parameterized queries to prevent SQL injection attacks.

Compliant code

<?php

namespace App\\Http\\Controllers;

use Illuminate\\Http\\Request;
use App\\User;
use Illuminate\\Support\\Facades\\Auth;
use Illuminate\\Support\\Facades\\Validator;

class UserController extends Controller
{
    public function __construct()
    {
        $this->middleware('auth');
    }

    public function updateUser(Request $request, $id)
    {
        $user = User::find($id);

        if(Auth::user()->id !== $user->id){
            return response()->json(['message' => 'Unauthorized'], 401);
        }

        $validator = Validator::make($request->all(), [
            'name' => 'required|max:255',
            'email' => 'required|email|max:255|unique:users,email,'.$user->id,
        ]);

        if ($validator->fails()) {
            return response()->json($validator->errors(), 400);
        }

        $user->name = $request->input('name');
        $user->email = $request->input('email');

        $user->save();

        return response()->json(['message' => 'User updated successfully']);
    }
}

The updated code now includes several security measures to prevent unauthorized access and data manipulation:

1. Authentication: The __construct() method now includes a middleware that checks if a user is authenticated before allowing them to access the updateUser method.

2. Authorization: Inside the updateUser method, we check if the authenticated user's ID matches the ID of the user they are trying to update. If not, an 'Unauthorized' message is returned with a 401 status code.

3. Input Validation: We use Laravel's built-in Validator to ensure that the 'name' and 'email' fields are in the correct format and do not contain malicious content. If the validation fails, the errors are returned with a 400 status code.

4. Preventing SQL Injection: Laravel's Eloquent ORM uses PDO parameter binding, which protects against SQL injection attacks. Therefore, the way we are updating the user's details is already safe from SQL injection.

These measures ensure that only authorized users can update their own details, and that they can only do so with valid input data.

References

• 115.Security controls bypass or absence