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php xss过滤

作者:用户 来源:互联网 时间:2017-12-01 19:45:07

用户

php xss过滤 - 摘要: 本文讲的是php xss过滤, XSS又叫CSS (Cross Site Script) ,跨站脚本攻击。它指的是恶意攻击者往Web页面里插入恶意html代码,当用户浏览该页之时,嵌入其中Web里面的html代码会被执行,进而达到某些人的攻击目的。 下面是thinkph

XSS又叫CSS (Cross Site Script) ,跨站脚本攻击。它指的是恶意攻击者往Web页面里插入恶意html代码,当用户浏览该页之时,嵌入其中Web里面的html代码会被执行,进而达到某些人的攻击目的。

下面是thinkphp里面的一段代码,用于过滤xss

ThinkPHP/Code/ThinkPHP/Common/extend.php

<?php	 	 /** 	 * @去除XSS(跨站脚本攻击)的函数 	 * @par $val 字符串参数,可能包含恶意的脚本代码如<script language="javascript">alert("hello world");</script> 	 * @return处理后的字符串 	 * @Recoded By Androidyue 	 **/	 function RemoveXSS($val) {	 		 // remove all non-printable characters. CR(0a) and LF(0b) and TAB(9) are allowed	 		 // this prevents some character re-spacing such as <java/0script>	 		 // note that you have to handle splits with /n, /r, and /t later since they *are* allowed in some inputs	 		 $val = preg_replace('/([/x00-/x08,/x0b-/x0c,/x0e-/x19])/', '', $val);	 		 // straight replacements, the user should never need these since they're normal characters	 		 // this prevents like <IMG [email protected]:alert('XSS')>	 		 $search = 'abcdefghijklmnopqrstuvwxyz';			 $search .= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';	 		 $search .= '[email protected]#$%^&*()';			 $search .= '~`";:?+/={}[]-_|/'//';			 for ($i = 0; $i < strlen($search); $i++) {				 // ;? matches the ;, which is optional				 // 0{0,7} matches any padded zeros, which are optional and go up to 8 chars				 // @ @ search for the hex values				 $val = preg_replace('/([xX]0{0,8}'.dechex(ord($search[$i])).';?)/i', $search[$i], $val); // with a ;				 // @ @ 0{0,7} matches '0' zero to seven times	 			 $val = preg_replace('/(�{0,8}'.ord($search[$i]).';?)/', $search[$i], $val); // with a ;			 }			 // now the only remaining whitespace attacks are /t, /n, and /r			 $ra1 = Array('javascript', 'vbscript', 'expression', 'applet', 'meta', 'xml', 'blink', 'link', 'style', 'script', 'embed', 'object', 'iframe', 'frame', 'frameset', 'ilayer', 'layer', 'bgsound', 'title', 'base');			 $ra2 = Array('onabort', 'onactivate', 'onafterprint', 'onafterupdate', 'onbeforeactivate', 'onbeforecopy', 'onbeforecut', 'onbeforedeactivate', 'onbeforeeditfocus', 'onbeforepaste', 'onbeforeprint', 'onbeforeunload', 'onbeforeupdate', 'onblur', 'onbounce', 'oncellchange', 'onchange', 'onclick', 'oncontextmenu', 'oncontrolselect', 'oncopy', 'oncut', 'ondataavailable', 'ondatasetchanged', 'ondatasetcomplete', 'ondblclick', 'ondeactivate', 'ondrag', 'ondragend', 'ondragenter', 'ondragleave', 'ondragover', 'ondragstart', 'ondrop', 'onerror', 'onerrorupdate', 'onfilterchange', 'onfinish', 'onfocus', 'onfocusin', 'onfocusout', 'onhelp', 'onkeydown', 'onkeypress', 'onkeyup', 'onlayoutcomplete', 'onload', 'onlosecapture', 'onmousedown', 'onmouseenter', 'onmouseleave', 'onmousemove', 'onmouseout', 'onmouseover', 'onmouseup', 'onmousewheel', 'onmove', 'onmoveend', 'onmovestart', 'onpaste', 'onpropertychange', 'onreadystatechange', 'onreset', 'onresize', 'onresizeend', 'onresizestart', 'onrowenter', 'onrowexit', 'onrowsdelete', 'onrowsinserted', 'onscroll', 'onselect', 'onselectionchange', 'onselectstart', 'onstart', 'onstop', 'onsubmit', 'onunload');			 $ra = array_merge($ra1, $ra2);			 $found = true; // keep replacing as long as the previous round replaced something			 while ($found == true) {				 $val_before = $val;				 for ($i = 0; $i < sizeof($ra); $i++) {					 $pattern = '/';					 for ($j = 0; $j < strlen($ra[$i]); $j++) {						 if ($j > 0) {							 $pattern .= '(';	 						 $pattern .= '([xX]0{0,8}([9ab]);)';							 $pattern .= '|';	 						 $pattern .= '|(�{0,8}([9|10|13]);)';							 $pattern .= ')*';						 }						 $pattern .= $ra[$i][$j];					 }					 $pattern .= '/i';	 				 $replacement = substr($ra[$i], 0, 2).'<x>'.substr($ra[$i], 2); // add in <> to nerf the tag	 				 $val = preg_replace($pattern, $replacement, $val); // filter out the hex tags	 				 if ($val_before == $val) {	 					 // no replacements were made, so exit the loop	 					 $found = false;	 				 }	 			 }	 		 }	 		 return $val;	 	 }	 //测试一下效果	 //echo RemoveXSS("<script language='javascript'>alert('hello world');</script>") ;	 ?>

此外还有一个工具:HTML Purifier,比上面的文档效率高一倍,欲知后事如何,且听下回分解。

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