Overcoming CSRF: Foolproof PHP Protection Strategies

2.1 Using CSRF Token

php editor Zimo brings you PHP protection strategies to overcome CSRF difficulties. CSRF (cross-site request forgery) is a common network attack method. In order to effectively prevent such attacks, PHP developers need to take a series of measures, such as using CSRF tokens, verifying HTTP Referer, double confirmation and other methods to ensure that the website Data security. This article will introduce these protection strategies in detail to help you establish a foolproof PHP protection system to protect your website from the threat of CSRF attacks.

2.2 Use Referer Header

Referer Header is a Http request header that contains the URL of the request source. The server can check the Referer Header to determine if the request comes from a legitimate source. If the Referer Header does not exist or points to an illegal source, it is considered a CSRF attack and the request will be rejected.

2.3 Using SameSite Cookie

SameSite Cookie is a new Cookie attribute that can be used to limit the scope of Cookie. The SameSite cookie can be set to "Strict", "Lax", or "None". The cookie will be sent on cross-site requests only if the SameSite cookie is set to "Strict".

2.4 Using dual submission token mode

Double submission token mode is a classic method to prevent CSRF attacks. In dual-submit token mode, the server generates a random token with each request and stores the token in a hidden form field. When the user submits the form, the server verifies whether the token in the hidden form field is consistent with the token in the session. If it is inconsistent, it considers a CSRF attack and rejects the request.

3. Demo code

The following is a PHP code that uses CSRF Token to prevent CSRF attacks:

<?php
// 生成 CSRF Token
$csrf_token = bin2hex(random_bytes(32));

// 将 CSRF Token 存储在会话中
$_SESSioN["csrf_token"] = $csrf_token;
?>

<fORM action="submit.php" method="post">
<input type="hidden" name="csrf_token" value="<?php echo $csrf_token; ?>">
<!-- 表单其他字段 -->
<input type="submit" value="提交">
</form>

In the submit.php file, you can verify the CSRF Token as follows:

<?php
// 获取请求中的 CSRF Token
$csrf_token = $_POST["csrf_token"];

// 获取会话中的 CSRF Token
$session_csrf_token = $_SESSION["csrf_token"];

// 比较两个 CSRF Token
if ($csrf_token !== $session_csrf_token) {
// 认为是 CSRF 攻击，拒绝请求
die("CSRF attack detected!");
}

// 处理表单提交
// ...

4. Summary

By using CSRF Token, Referer Header, SameSite Cookie or dual submission token mode, PHP developers can effectively prevent CSRF attacks and protect the security of WEB applications .

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