保护您的 PHP 应用程序免受常见漏洞影响的基本安全实践

<?php// insecure version$user_id = $_get['id'];$query = "select * from users where id = '$user_id'";$result = mysqli_query($connection, $query);// secure version$user_id = $_get['id'];$stmt = $connection->prepare("select * from users where id = ?");$stmt->bind_param("i", $user_id);  // "i" for integer$stmt->execute();$result = $stmt->get_result();?>

<?php// insecure versionecho "<p>welcome, " . $_get['username'] . "</p>";// secure versionecho "<p>welcome, " . htmlspecialchars($_get['username'], ent_quotes, 'utf-8') . "</p>";?>

<?php// generate csrf tokensession_start();if (empty($_session['csrf_token'])) {    $_session['csrf_token'] = bin2hex(random_bytes(32));}// add token to formecho '<form method="post" action="submit.php">';echo '<input type="hidden" name="csrf_token" value="' . $_session['csrf_token'] . '">';echo '<input type="text" name="data">';echo '<input type="submit" value="submit">';echo '</form>';?>

<?phpsession_start();if ($_post['csrf_token'] !== $_session['csrf_token']) {    die("csrf token validation failed.");}// process form data$data = $_post['data'];?>

<?phpsession_start();// regenerate session id to avoid fixation attackssession_regenerate_id(true);// configure secure session parametersini_set('session.cookie_httponly', 1); // prevent javascript access to session cookiesini_set('session.cookie_secure', 1);   // ensure cookies are sent over httpsini_set('session.use_strict_mode', 1); // prevent accepting uninitialized session ids// set session timeout$_session['last_activity'] = time(); // update last activity timeif (time() - $_session['last_activity'] > 1800) { // 30 minutes timeout    session_unset();    session_destroy();    session_start();}?>

<?php$allowed_extensions = ['jpg', 'jpeg', 'png', 'gif'];$file_name = $_files['file']['name'];$file_extension = pathinfo($file_name, pathinfo_extension);// check file extensionif (!in_array($file_extension, $allowed_extensions)) {    die("invalid file type.");}// store in a safe location (outside web root) with a unique name$target_dir = "/var/www/uploads/";$target_file = $target_dir . basename($file_name);if (move_uploaded_file($_files['file']['tmp_name'], $target_file)) {    echo "file uploaded successfully.";} else {    echo "file upload failed.";}?>

header set content-security-policy "default-src 'self'; script-src 'self' 'unsafe-inline' https://trustedscripts.com"

<?php// Validate integer input$age = filter_input(INPUT_GET, 'age', FILTER_VALIDATE_INT);if ($age === false) {    die("Invalid age value.");}// Sanitize string input$username = filter_input(INPUT_POST, 'username', FILTER_SANITIZE_STRING);?>