對于Yii2的XSS攻擊防范策略的方法解析

2020-03-22 18:39:02

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

本文實例講述了Yii2的XSS攻擊防范策略。分享給大家供大家參考，具體如下：

XSS 漏洞修復

原則：不相信客戶輸入的數據
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，只允許用戶輸入數字。而數字之外的字符都過濾掉。
③ 對數據進行Html Encode 處理
④ 過濾或移除特殊的Html標簽，例如: script, iframe , for , for , quot for
⑤ 過濾JavaScript 事件的標簽。例如 quot;, onfocus 等等。

Yii中的XSS防范

 ?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 `$content` will not be further encoded.* @return string the encoded content* @see decode()* @see http://www.php.net/manual/en/function.htmlspecialchars.phppublic static function encode($content, $doubleEncode = true) return htmlspecialchars($content, ENT_QUOTES | ENT_SUBSTITUTE, Yii::$app- charset, $doubleEncode);}

htmlspecialchars htmlentities urlencode 三者的區別：

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 quotes unconverted.
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 Replacement Character U+FFFD (UTF-8) or FFFD; (otherwise) instead of 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. This may be useful, for 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.
ENT_XHTML Handle code as XHTML.
ENT_HTML5 Handle code 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 is set.
(less than) becomes
(greater than) becomes

 ?php$new = htmlspecialchars( a href= test Test /a , ENT_QUOTES);echo $new; // a href= test 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$str = A quote is b bold /b // Outputs: A quote is b bold /b echo htmlentities($str);// Outputs: A quote is b bold /b echo htmlentities($str, ENT_QUOTES);?

urlencode

URL 編碼是為了符合url的規范。因為在標準的url規范中中文和很多的字符是不允許出現在url中的。

例如在baidu中搜索測試漢字。 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編碼就是：把所有非字母數字字符都將被替換成百分號（%）后跟兩位十六進制數，空格則編碼為加號（+）
此字符串中除了 -_. 之外的所有非字母數字字符都將被替換成百分號（%）后跟兩位十六進制數，空格則編碼為加號（+）。此編碼與 WWW 表單 POST 數據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。由于歷史原因，此編碼在將空格編碼為加號（+）方面與 RFC1738 編碼（參見 rawurlencode()）不同。

 ?phpecho a href= mycgi?foo= , urlencode($userinput), ?

 ?php$query_string = foo= . urlencode($foo) . bar= . urlencode($bar);echo a href= mycgi? . htmlentities($query_string) . ?

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