<?php
class Filter_Xss
{
* * /**
* * ** Remove XSS attacks that came in the input
* * **
* * ** Function taken from:
* * ** http://quickwired.com/smallprojects/php_xss_filter_function.php
* * ** and alter to use in application
* * **
* * ** @param string $value The value to filter
* * ** @return string
* * **/
* * public function filterXss($params, $returnStr = false)
* * {
*
* * * * foreach($params as $key => $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-\x20])/', '', $val); *
* * * * * * * * /**
* * * * * * * * ** straight replacements, the user should never need these since they're normal characters
* * * * * * * * ** this prevents like
* * * * * * * * ** <IMG SRC=@avascript:alert('XSS')>
* * * * * * * * **/
* * * * * * * * $search = 'abcdefghijklmnopqrstuvwxyz';
* * * * * * * * $search .= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
* * * * * * * * $search .= '1234567890!@#$%^&*()';
* * * * * * * * $search .= '~`";:?+/={}[]-_|\'\\';
* * * * * * * * for($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
* * * * * * * * * * **/
* * * * * * * * * * $val = preg_replace('/(&#[x|X]0{0,8}'.dechex(ord($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'
* * * * * * * * );
*
* * * * * * * * $found = true; // keep replacing as long as the previous round replaced something
* * * * * * * * while($found){
* * * * * * * * * * $val_before = $val;
* * * * * * * * * * for($i = 0; $i < sizeof($ra); $i++){ * * * * * * * * * * * * $pattern = '/';
* * * * * * * * * * * * for($j = 0; $j < strlen($ra[$i]); $j++){ * * * * * * * * * * * * * * if($j > 0){
* * * * * * * * * * * * * * * * $pattern .= '(';
* * * * * * * * * * * * * * * * $pattern .= '(&#[x|X]0{0,8}([9][a][b]);?)?';
* * * * * * * * * * * * * * * * $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;
* * * * * * * * * * * * }
* * * * * * * * * * }
* * * * * * * * }
* * * * * * }
* * * * * * $params[$key] = is_array($val) ?
$this->filterXss($val) : $val; * * * * }
*
* * * * return $returnStr ? $params[0] : $params;
* * }
*
* * /**
* * ** Remove XSS attacks and remove tags and extra white spaces
* * ** that came in the input before and after
* * **
* * ** @param string|array $params The value to filter
* * ** @param bool Set this if you want to return string value
* * ** @return string|array
* * **/
* * public function realEscapeString($params, $returnStr = false)
* * {
* * * * /**
* * * * ** Check for XSS atacks
* * * * **/
* * * * $params = $this->filterXss($params, $returnStr);
*
*
* * * * foreach($params as $k => $v){
* * * * * * /**
* * * * * * ** Recursive, re-send all values that are arrays
* * * * * * **/
* * * * * * * * $params[$k] = $this->realEscapeString($v);
* * * * * * * * continue;
* * * * * * }
* * * * * * /**
* * * * * * ** Decode all hexadecimal values (urldecode and html_entity_decode)
* * * * * * ** Clean up all values (strip_tags)
* * * * * * ** Erase all white space before and after string (trim)
* * * * * * **/
* * * * * * $params[$k] = strip_tags($params[$k]); * * * * * * $params[$k] = trim($params[$k]); * * * * }
*
* * * * return $returnStr ? $params[0] : $params;
* * }
}
*
//Uso
$filter = new Filter_Xss();
$values = $filter->filterXss($_POST);
*
// Sin HTML
$filter = new Filter_Xss();
$values = $filter->realEscapeString($_POST);
*
*
// Filtrar un campo y devolver resultado tipo string
$filter = new Filter_Xss();
$values = $filter->filterXss($_POST['foo'], true);
*
// Sin HTML
$filter = new Filter_Xss();
$values = $filter->realEscapeString($_POST['foo'], true);
