本文实例讲述了PHP实现XSS安全过滤的方法。分享给大家供大家参考。具体如下：
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function remove_xss($val) {
// remove all non-printable characters. CR(0a) and LF(0b) and TAB(9) are allowed
// this prevents some character re-spacing such as
// 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 )
$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
$val = preg_replace('/(&#[xX]0{0,8}'.dechex(ord($search[$i])).';?)/i',$search[$i],$val); // with a ;
// @ @ 0{0,7} matches '0' zero to seven times
$val = preg_replace('/(�{0,8}'.ord($search[$i]).';?)/',$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[$i],2).''.substr($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;
}
希望本文所述对大家的PHP程序设计有所帮助。
原文链接：https://www.f2er.com/php/21398.html