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對於Yii2的XSS攻擊防範策略的方法解析

不言原創: 2018-06-19 13:44:012162瀏覽

這篇文章主要介紹了Yii2的XSS攻擊防範策略,較為詳細的分析了XSS攻擊的原理及Yii2相應的防範策略,需要的朋友可以參考下

本文實例講述了Yii2的XSS攻擊防範策略。分享給大家供大家參考，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>2cacc6d41bbb37262a98f745aa00fbf0中

① 將重要的cookie標記為http only, 這樣的話Javascript 中的document.cookie語句就不能獲取到cookie了.
② 只允許用戶輸入我們期望的數據。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 , f7142607ca3bcca4ac1473eda942a5a5 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) ?>

此方法的原始碼：

/**
* 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);
}

htmlspecialchars & htmlentities & urlencode 三者的差異：

http://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_NOQUOTES Will leave both double and single.
ENT_NOQUOTES Will. 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 FFplacement Character FFFDFD; 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。 , 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.##ENT_XHTMLHandleHan as HTML 5.

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 ]
    ]
  ] 
)

The translations performed are:

& (ampersand) becomes &

" (double quote) becomes " when ENT_NOQUOTES is not set.

' (single quote) becomes ' (or ') only when ENT_QUOTES ESis set .
3d41d43f2529bef045c502fdf917436d (greater than) becomes >

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

#htmlentities

Convert all applicable characters to HTML entities

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

<?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=��i��&rsv_bp=0&rsv_spt=3&inputT=7477

#所謂URL編碼就是：　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元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;;
?>

#以上就是本文的全部內容，希望對大家的學習有幫助，更多相關內容請關注PHP中文網！

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