Attack and defense game, step by step: PHP cross-site request forgery (CSRF) prevention strategy

php editor Yuzai will take you to explore the "offensive and defensive game, step by step: PHP cross-site request forgery (CSRF) prevention strategies". CSRF attacks are a common network security threat that deceive users into triggering malicious operations by disguising user requests. In the PHP development process, it is particularly important to effectively prevent CSRF attacks. This article will provide an in-depth analysis of the principles of CSRF attacks and introduce prevention strategies against CSRF attacks to help developers better protect website security.

• Steal sensitive information: An attacker can steal the victim's login credentials, credit card information, email address and other sensitive information through CSRF attacks.
• Destroy website data: An attacker can modify or delete the website's data through CSRF attacks, causing the website to fail to function properly.
• Spread malware:An attacker can install malware on the victim's computer through a CSRF attack, thereby taking control of the victim's computer.

CSRF attack prevention measures

In order to prevent CSRF attacks, website administrators and developers can take a variety of measures, including:

• Use CSRF token: The CSRF token is a randomly generated unique string. The website will embed a CSRF token in the form when generating each form. When a user submits a form, the website verifies that the CSRF token in the form is consistent with the CSRF token on the server. If they are inconsistent, the form has been tampered with and the website will refuse to process the form.
• Use the same origin policy: The same origin policy is a browser security mechanism that prevents scripts from different origins from accessing each other. Website administrators and developers can prevent CSRF attacks by using the same-origin policy in their websites.
• Validate user input: Website administrators and developers should verify user input to ensure that the data entered by the user is legal. If the data entered by the user is illegal, the website should refuse to process the user input.

Code Example

The following code example demonstrates how to use CSRF tokens to protect against CSRF attacks:

<?PHP
// 生成CSRF令牌
$csrf_token = bin2hex(random_bytes(32));

// 将CSRF令牌嵌入表单中
echo "<input type="hidden" name="csrf_token" value="" . $csrf_token . "">";

// 当用户提交表单时，验证CSRF令牌是否与服务器上的CSRF令牌一致
if ($_POST["csrf_token"] != $csrf_token) {
// 表单已被篡改，拒绝处理表单
die("Invalid CSRF token");
} else {
// 表单是合法的，处理表单
// ...
}
?>

Summarize

Cross-site request forgery (CSRF) is a common network attack method that allows attackers to initiate malicious requests to trusted websites through the victim's browser, thereby causing damage or theft to the website. Sensitive information. Website administrators and developers can protect against CSRF attacks by using measures such as CSRF tokens, same-origin policies, and validating user input.

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