Yii2的XSS攻擊防範策略分析

本文實例講述了Yii2的XSS攻擊防範策略。分享給大家參考，具體如下：

XSS 漏洞修復

原則：　不相信客戶輸入的資料
注意: 攻擊代碼不一定在<script></script>中

① 將重要的cookie標記為http only, 這樣的話Javascript 中的document.cookie語句就不能取得到cookie了.
② 只允許使用者輸入我們期望的資料。 例如：　年齡的textbox中，只允許使用者輸入數字。 而數字之外的字元都被過濾掉。
③ 對資料進行Html Encode 處理
④ 過濾或移除特殊的Html標籤， 例如: script, iframe , for >, " for
⑤ 過濾JavaScript 事件的標籤。例如"onclick=", " onfocus" 等等。

Yii中的XSS防範

<?php echo CHtml::encode($user->name) ?>

   

此方法的源碼：

/**
* Encodes special characters into HTML entities.
* The [[\yii\base\Application::charset|application charset]] will be used for encoding.
* @param string $content the content to be encoded
* @param boolean $doubleEncode whether to encode HTML entities in `$content`. If false,
* HTML entities in `$content` will not be further encoded.
* @return string the encoded content
* @see decode()
* @see http://www.php.net/manual/en/function.htmlspecialchars.php
*/
public static function encode($content, $doubleEncode = true)
{
  return htmlspecialchars($content, ENT_QUOTES | ENT_SUBSTITUTE, Yii::$app->charset, $doubleEncode);
}

 ://php.net /manual/zh/function.htmlspecialchars.php

http://php.net/manual/zh/function.htmlentities.php

http://cn2.php.net/manual/zh/function.urlencode.php

Available flags constants

Constant Name Description

ENT_COMPAT Will convert double-quotes and leave single-quotes alone.
ENT_QUOTES Will convert both double and single quotes
ENT_QUOTES Willoth both double and single quotes

ENT_QUOTES Willoth both double and single quotesp. ENT_IGNORE Silently discard invalid code unit sequences instead of returning an empty string. Using this flag is discouraged as it » may have security implications.

ENT_SUBSTITUTE Replace invalid code unit sequences with a Unicode Replace Character U. returning an empty string.
ENT_DISALLOWED Replace invalid code points for the given document type with a Unicode Replacement Character U+FFFD (UTF-8) or &#FFFD; (otherwise) instead of leaving them as is fors. instance, to ensure the well-formedness of XML documents with embedded external content.
ENT_HTML401 Handle code as HTML 4.01.
ENT_XML1 Handle code as XML 1.🜎

htmlspecialchars

Convert special characters to HTML entities

string htmlspecialchars (
      string $string
      [, int $flags = ENT_COMPAT | ENT_HTML401
      [, string $encoding = ini_get("default_charset")
      [, bool $double_encode = true ]
    ]
  ]
)

Convert special characters to HTML entities

<?php
$new = htmlspecialchars("<a href=&#39;test&#39;>Test</a>", ENT_QUOTES);
echo $new; // <a href=&#39;test&#39;>Test</a>
?>

   

The translations performed are:

（

' (single quote) becomes ' (or ') only when ENT_QUOTES is set.

< (less than) becomes <

> (greater than) becomes >

string htmlentities (
      string $string
      [, int $flags = ENT_COMPAT | ENT_HTML401
      [, string $encoding = ini_get("default_charset")
      [, bool $double_encode = true ]
    ]
  ]
)

   

🜥 html

<?php
$str = "A &#39;quote&#39; is <b>bold</b>";
// Outputs: A &#39;quote&#39; is <b>bold</b>
echo htmlentities($str);
// Outputs: A &#39;quote&#39; is <b>bold</b>
echo htmlentities($str, ENT_QUOTES);
?>

urlencode

URL 編碼是為了符合url的規範。因為在標準的url規範中中文和很多的字元是不允許出現在url中的。

例如在baidu中搜尋"測試漢字"。 URL會變成

http://www.baidu.com/s?wd=%B2%E2%CA%D4%BA%BA%D7%D6&rsv_bp=0&rsv_spt=3&inputT=7477

所謂URL把編碼：　把所有非字母數字字元都將被替換成百分號（%）後跟兩位十六進制數，空格則編碼為加號（+）

　此字串中除了-_. 之外的所有非字母數字字符都將被替換成百分號（%）後面跟著兩位十六進位數，空格編碼為加號（+）。此編碼與 WWW 表單 POST 資料的編碼方式是一樣的，同時與 application/x-www-form-urlencoded 的媒體類型編碼方式一樣。由於歷史原因，此編碼在將空格編碼為加號（+）方面與 RFC1738 編碼（請參閱 rawurlencode()）不同。

<?php
echo &#39;<a href="mycgi?foo=&#39;, urlencode($userinput), &#39;">&#39;;
?>

<?php
$query_string = &#39;foo=&#39; . urlencode($foo) . &#39;&bar=&#39; . urlencode($bar);
echo &#39;<a href="mycgi?&#39; . htmlentities($query_string) . &#39;">&#39;;
?>

希望本文所述對大家基於Yii框架的PHP程式設計有所幫助。

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