PHP data filtering: preventing XSS and CSRF attacks
Jul 29, 2023 pm 03:33 PMPHP Data Filtering: Preventing XSS and CSRF Attacks
With the development of the Internet, network security has become one of the focuses of people's attention. In website development, it is very important to filter and verify user-submitted data, especially to prevent XSS (cross-site scripting attacks) and CSRF (cross-site request forgery attacks) attacks. This article will introduce how to use PHP to prevent these two common security vulnerabilities and provide some sample code for reference.
- Preventing XSS attacks
XSS attacks refer to malicious attackers tampering with web page content by injecting malicious scripts or codes to steal user sensitive information or spread malware. In order to prevent XSS attacks, we need to filter and escape the data entered by the user.
(1) Use the htmlspecialchars() function to escape HTML special characters.
$name = $_POST['name']; $filtered_name = htmlspecialchars($name, ENT_QUOTES, 'UTF-8');
(2) Use regular expressions to filter user input.
$name = $_POST['name']; $pattern = '/^[a-zA-Z0-9]+$/'; if (preg_match($pattern, $name)) { // 用戶輸入合法 } else { // 用戶輸入不合法 }
- Preventing CSRF attacks
CSRF attacks refer to attackers performing unauthorized operations by forging user requests, such as modifying user information, initiating malicious transfers, etc. To prevent CSRF attacks, we can take the following measures.
(1) Use CSRF token verification.
session_start(); $csrf_token = bin2hex(random_bytes(32)); // 生成隨機(jī)的令牌 $_SESSION['csrf_token'] = $csrf_token; // 在表單中添加令牌 echo "<input type='hidden' name='csrf_token' value='{$csrf_token}'>"; // 驗(yàn)證令牌 if ($_POST['csrf_token'] === $_SESSION['csrf_token']) { // 令牌驗(yàn)證通過 } else { // 令牌驗(yàn)證失敗 }
(2) Limit request sources.
if ($_SERVER['HTTP_REFERER'] !== 'http://www.example.com') { // 請求來源不合法 } else { // 請求來源合法 }
To sum up, filtering and verifying user-submitted data is an important step to ensure website security. By escaping HTML special characters, using regular expressions to filter user input, using CSRF token verification and limiting request sources, we can effectively prevent XSS and CSRF attacks. However, security is an ongoing process, and we need to constantly update and strengthen security measures to improve the security of the website.
Reference materials:
- PHP official documentation (https://www.php.net/)
- OWASP official website (https://owasp.org /)
The above is the detailed content of PHP data filtering: preventing XSS and CSRF attacks. For more information, please follow other related articles on the PHP Chinese website!

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