CSRF Protection

• Introduction
• Preventing CSRF Requests
  • Excluding URIs
• X-CSRF-Token
• X-XSRF-Token

Introduction

Cross-site request forgeries are a type of malicious exploit whereby unauthorized commands are performed on behalf of an authenticated user. Thankfully, Laravel makes it easy to protect your application from cross-site request forgery (CSRF) attacks.

An Explanation of the Vulnerability

In case you're not familiar with cross-site request forgeries, let's discuss an example of how this vulnerability can be exploited. Imagine your application has a /user/email route that accepts a POST request to change the authenticated user's email address. Most likely, this route expects an email input field to contain the email address the user would like to begin using.

Without CSRF protection, a malicious website could create an HTML form that points to your application's /user/email route and submits the malicious user's own email address:

<form action="https://your-application.com/user/email" method="POST">
    <input type="email" value="malicious-email@example.com">
</form>

<script>
    document.forms[0].submit();
</script>

If the malicious website automatically submits the form when the page is loaded, the malicious user only needs to lure an unsuspecting user of your application to visit their website and their email address will be changed in your application.

To prevent this vulnerability, we need to inspect every incoming POST, PUT, PATCH, or DELETE request for a secret session value that the malicious application is unable to access.

阻止 CSRF 请求

Laravel 会自动为应用程序管理的每个活动 用户会话 生成一个 CSRF 「令牌」。此令牌用于验证经过身份验证的用户是否是实际向应用程序发出请求的人。由于此令牌存储在用户的会话中，并且每次重新生成会话时都会发生变化，因此恶意应用程序无法访问它。

当前会话的 CSRF 令牌可以通过请求的会话或 csrf_token 辅助函数来访问：

use Illuminate\Http\Request;

Route::get('/token', function (Request $request) {
    $token = $request->session()->token();

    $token = csrf_token();

    // ...
});

每当你在应用程序中定义 POST 、 PUT 、 PATCH 或 DELETE HTML 表单时，都应该在表单中包含一个隐藏的 CSRF _token 字段，以便 CSRF 保护中间件可以验证请求。为了方便起见，你可以使用 @csrf Blade 指令来生成隐藏令牌输入字段：

<form method="POST" action="/profile">
    @csrf

    <!-- Equivalent to... -->
    <input type="hidden" name="_token" value="{{ csrf_token() }}" />
</form>

默认情况下包含在 web 中间件组中的 Illuminate\Foundation\Http\Middleware\ValidateCsrfToken 中间件 将自动验证请求输入中的令牌是否与会话中存储的令牌匹配。当这两个令牌匹配时，我们就知道经过身份验证的用户是发起请求的用户。

CSRF Tokens & SPAs

如果你正在构建使用 Laravel 作为 API 后端的 SPA，则应查阅 Laravel Sanctum 文档，了解有关使用 API 进行身份验证和防范 CSRF 漏洞的信息。

dkp 翻译于 2周前

0 重译

Excluding URIs From CSRF Protection

Sometimes you may wish to exclude a set of URIs from CSRF protection. For example, if you are using Stripe to process payments and are utilizing their webhook system, you will need to exclude your Stripe webhook handler route from CSRF protection since Stripe will not know what CSRF token to send to your routes.

Typically, you should place these kinds of routes outside of the web middleware group that Laravel applies to all routes in the routes/web.php file. However, you may also exclude specific routes by providing their URIs to the validateCsrfTokens method in your application's bootstrap/app.php file:

->withMiddleware(function (Middleware $middleware) {
    $middleware->validateCsrfTokens(except: [
        'stripe/*',
        'http://example.com/foo/bar',
        'http://example.com/foo/*',
    ]);
})

[!NOTE]
For convenience, the CSRF middleware is automatically disabled for all routes when running tests.

X-CSRF-TOKEN

In addition to checking for the CSRF token as a POST parameter, the Illuminate\Foundation\Http\Middleware\ValidateCsrfToken middleware, which is included in the web middleware group by default, will also check for the X-CSRF-TOKEN request header. You could, for example, store the token in an HTML meta tag:

<meta name="csrf-token" content="{{ csrf_token() }}">

Then, you can instruct a library like jQuery to automatically add the token to all request headers. This provides simple, convenient CSRF protection for your AJAX based applications using legacy JavaScript technology:

$.ajaxSetup({
    headers: {
        'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
    }
});

X-XSRF-TOKEN

Laravel stores the current CSRF token in an encrypted XSRF-TOKEN cookie that is included with each response generated by the framework. You can use the cookie value to set the X-XSRF-TOKEN request header.

This cookie is primarily sent as a developer convenience since some JavaScript frameworks and libraries, like Angular and Axios, automatically place its value in the X-XSRF-TOKEN header on same-origin requests.

[!NOTE]
By default, the resources/js/bootstrap.js file includes the Axios HTTP library which will automatically send the X-XSRF-TOKEN header for you.