How to use PHP forms to prevent iframe hijacking attacks

With the popularization of the Internet, network security issues have become increasingly prominent. Among them, iframe hijacking attack is a common means of network attack. This attack method mainly loads the attacker's malicious page by embedding iframe tags in the Web page, thereby achieving the purpose of controlling the user's browser. In order to prevent iframe hijacking attacks, this article will introduce how to use PHP forms to implement security prevention.

1. Detection environment

In PHP development, use the following code to detect whether you are currently in an iframe environment:

if (isset($_SERVER['HTTP_REFERER']) && !empty($_SERVER['HTTP_REFERER'])) {
  if (strpos($_SERVER['HTTP_REFERER'], $_SERVER['HTTP_HOST']) === false) {
    //不在当前域名内，可能受到恶意攻击
  }
}

Among them, HTTP_REFERER is the HTTP protocol A field in the request header that is used to track the source address of the current requested page. By determining whether the source address is the domain name of the current website, iframe hijacking attacks can be effectively prevented.

2. Form passing parameters

When submitting data in the form, you can use the following code to filter and escape parameters:

function check_input($data) {
  $data = trim($data);
  $data = stripslashes($data);
  $data = htmlspecialchars($data);
  return $data;
}

For special characters , such as 95ec6993dc754240360e28e0de8de30a, ', ", &, etc., can be escaped using the htmlspecialchars() function to avoid security vulnerabilities caused by the inability to correctly identify these characters.

3. Verification code Mechanism

In order to verify user identity more securely, a verification code mechanism can be added when the form is submitted. The verification code can increase the difficulty for attackers to crack, thereby improving the security of the form.

The generation and verification of the verification code can be achieved through the following code:

session_start();
$code = '';
for ($i = 0; $i < 4; $i++) {
  $code .= rand(0, 9);
}
$_SESSION['code'] = $code;
$im = imagecreate(58, 23);
$bg_color = imagecolorallocate($im, 225, 225, 225);
$font_color = imagecolorallocate($im, 0, 0, 0);
imagestring($im, 5, 10, 4,  $code, $font_color);
header('Content-type: image/png');
imagepng($im);
imagedestroy($im);

When submitting the form, the following code can be used to verify the verification code:

if ($_POST['code'] != $_SESSION['code']) {
  //验证码错误
}

4. Backend data filtering

In PHP, you can use the following code to filter and verify the data submitted by the form:

$username = check_input($_POST['username']);
if (!preg_match("/^[a-zA-Z0-9_]*$/", $username)) {
  // 用户名格式错误
}

Among them, the preg_match() function can be used to verify whether the string entered by the user matches Specified regular expression. When writing regular expressions, comprehensive considerations should be taken to avoid security vulnerabilities caused by defects in regular expressions.

In summary, by detecting the current environment, form parameter passing, and verification code mechanisms As well as back-end data filtering, we can effectively prevent iframe hijacking attacks. In PHP development, by rationally applying the above security measures, we can provide users with more secure and reliable services.

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