How to protect against clickjacking attacks using PHP forms

With the development of the Internet, clickjacking attacks have become a major problem in Internet security. Clickjacking attacks refer to attackers using specific technical means to cover a transparent layer on a web page, causing users to click where they shouldn't, thereby performing some unpredictable operations, such as downloading malicious programs, transferring money, etc. In order to protect users' security, we need to add clickjacking prevention technology to the web page. Here's how to use PHP forms to prevent clickjacking attacks.

1. The principle of click hijacking

Before introducing how to prevent click hijacking attacks, you need to first understand the principles of click hijacking attacks. A clickjacking attack is actually a cross-domain attack. The attacker overlays the target webpage on his own webpage through iframe and other methods, and then sets transparency or other methods to make the user mistakenly think it is the target webpage, thereby triggering certain clicks. Unsafe operation.

2. Methods to prevent click hijacking

1. Set X-Frame-Options

X-Frame-Options is an HTTP response header, which includes three options:

• DENY: The page cannot be displayed as a subpage of an iframe
• SAMEORIGIN: The page can only be embedded in pages with the same domain name
• ALLOW-FROM uri: Restricted pages Can only be embedded in the specified uri

Using X-Frame-Options can prevent web pages from being embedded in non-secure web pages, thus effectively preventing click hijacking attacks.

In PHP, you can set X-Frame-Options through the following code:

header('X-Frame-Options: DENY');

2. Use random Token

Using random Token is a widely used prevention method. Before clicking, you need to generate a Token and then store the Token in the session. When the user submits the form, we need to verify the correctness of the Token in the background. If the Token is incorrect, the user is prohibited from submitting the form.

The following is the PHP code implementation:

session_start();
if(!isset($_SESSION['token'])){
  $_SESSION['token']=md5(uniqid(rand(), true));
}
$token = $_SESSION['token'];

//生成Token隐藏在表单中

$formhtml="<form>"
  ."<input type='hidden' name='token' value='".$token."'>"
  ."</form>";
echo $formhtml;

//处理表单时验证Token的正确性，如果不正确则禁止提交

if(isset($_POST['token']) && $_POST['token'] !== $token) {
  die("Token Mismatch");
}

3. Summary

Clickjacking attacks have become a very common network security threat, which not only puts users at risk, but also causing economic losses. In order to prevent clickjacking attacks, using X-Frame-Options and random Token are very effective methods. When writing code, be sure to include these precautions to protect your users.

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