dedecms入侵

// 示例代码：使用PDO防止SQL注入
try {
    $pdo = new PDO('mysql:host=localhost;dbname=test', 'username', 'password');
    $stmt = $pdo->prepare('SELECT * FROM users WHERE username = :username');
    $stmt->bindParam(':username', $username);
    $username = $_POST['username'];
    $stmt->execute();
    $result = $stmt->fetchAll(PDO::FETCH_ASSOC);
} catch (PDOException $e) {
    echo 'Error: ' . $e->getMessage();
}

// 示例代码：限制文件上传类型和大小
if ($_FILES['file']['size'] > 1024 * 1024) {
    echo '文件大小超过限制';
    exit;
}
$allowed_types = array('jpg', 'jpeg', 'png', 'gif');
$file_ext = strtolower(pathinfo($_FILES['file']['name'], PATHINFO_EXTENSION));
if (!in_array($file_ext, $allowed_types)) {
    echo '不允许的文件类型';
    exit;
}

// 示例代码：防止代码执行
if (in_array($_GET['action'], array('edit', 'delete'))) {
    // 执行相应的操作
} else {
    echo '非法操作';
}

// 示例代码：防止XSS攻击
echo htmlspecialchars($content, ENT_QUOTES, 'UTF-8');