PHP如何防止XSS攻击
PHP防止XSS跨站脚本攻击的方法:是针对非法的HTML代码包括单双引号等，使用htmlspecialchars()函数 。
在使用htmlspecialchars()函数的时候注意第二个参数, 直接用htmlspecialchars($string) 的话,第二个参数默认是ENT_COMPAT,函数默认只是转化双引号(“), 不对单引号(‘)做转义.
所以,htmlspecialchars函数更多的时候要加上第二个参数, 应该这样用: htmlspecialchars($string,ENT_QUOTES).当然,如果需要不转化如何的引号,用htmlspecialchars($string,ENT_NOQUOTES).
另外, 尽量少用htmlentities, 在全部英文的时候htmlentities和htmlspecialchars没有区别,都可以达到目的.但是,中文情况下, htmlentities却会转化所有的html代码，连同里面的它无法识别的中文字符也给转化了。
htmlentities和htmlspecialchars这两个函数对 '之类的字符串支持不好,都不能转化, 所以用htmlentities和htmlspecialchars转化的字符串只能防止XSS攻击,不能防止SQL注入攻击.
所有有打印的语句如echo，print等 在打印前都要使用htmlentities() 进行过滤，这样可以防止Xss，注意中文要写出htmlentities($name,ENT_NOQUOTES,GB2312) 。
(1).网页不停地刷新 '<meta http-equiv="refresh" content="0;">'
(2).嵌入其它网站的链接 <iframe src=http://xxxx width=250 height=250></iframe> 除了通过正常途径输入XSS攻击字符外，还可以绕过JavaScript校验，通过修改请求达到XSS攻击的目的.
<?php //php防注入和XSS攻击通用过滤 $_GET && SafeFilter($_GET); $_POST && SafeFilter($_POST); $_COOKIE && SafeFilter($_COOKIE); function SafeFilter (&$arr) { $ra=Array('/([\x00-\x08,\x0b-\x0c,\x0e-\x19])/','/script/','/javascript/','/vbscript/','/expression/','/applet/' ,'/meta/','/xml/','/blink/','/link/','/style/','/embed/','/object/','/frame/','/layer/','/title/','/bgsound/' ,'/base/','/onload/','/onunload/','/onchange/','/onsubmit/','/onreset/','/onselect/','/onblur/','/onfocus/', '/onabort/','/onkeydown/','/onkeypress/','/onkeyup/','/onclick/','/ondblclick/','/onmousedown/','/onmousemove/' ,'/onmouseout/','/onmouseover/','/onmouseup/','/onunload/'); if (is_array($arr)) { foreach ($arr as $key => $value) { if (!is_array($value)) { if (!get_magic_quotes_gpc()) //不对magic_quotes_gpc转义过的字符使用addslashes(),避免双重转义。 { $value = addslashes($value); //给单引号（'）、双引号（"）、反斜线（\）与 NUL（NULL 字符） 加上反斜线转义 } $value = preg_replace($ra,'',$value); //删除非打印字符，粗暴式过滤xss可疑字符串 $arr[$key] = htmlentities(strip_tags($value)); //去除 HTML 和 PHP 标记并转换为 HTML 实体 } else { SafeFilter($arr[$key]); } } } } ?> $str = 'www.90boke.com<meta http-equiv="refresh" content="0;">'; SafeFilter ($str); //如果你把这个注释掉，提交之后就会无休止刷新 echo $str;
//------------------------------php防注入和XSS攻击通用过滤-----Start--------------------------------------------// function string_remove_xss($html) { preg_match_all("/\<([^\<]+)\>/is", $html, $ms); $searchs[] = '<'; $replaces[] = '<'; $searchs[] = '>'; $replaces[] = '>'; if ($ms[1]) { $allowtags = 'img|a|font|div|table|tbody|caption|tr|td|th|br|p|b|strong|i|u|em|span|ol|ul|li|blockquote'; $ms[1] = array_unique($ms[1]); foreach ($ms[1] as $value) { $searchs[] = "<".$value.">"; $value = str_replace('&', '_uch_tmp_str_', $value); $value = string_htmlspecialchars($value); $value = str_replace('_uch_tmp_str_', '&', $value); $value = str_replace(array('\\', '/*'), array('.', '/.'), $value); $skipkeys = 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','javascript','script','eval','behaviour','expression','style','class'); $skipstr = implode('|', $skipkeys); $value = preg_replace(array("/($skipstr)/i"), '.', $value); if (!preg_match("/^[\/|\s]?($allowtags)(\s+|$)/is", $value)) { $value = ''; } $replaces[] = empty($value) ? '' : "<" . str_replace('"', '"', $value) . ">"; } } $html = str_replace($searchs, $replaces, $html); return $html; } //php防注入和XSS攻击通用过滤 function string_htmlspecialchars($string, $flags = null) { if (is_array($string)) { foreach ($string as $key => $val) { $string[$key] = string_htmlspecialchars($val, $flags); } } else { if ($flags === null) { $string = str_replace(array('&', '"', '<', '>'), array('&', '"', '<', '>'), $string); if (strpos($string, '&#') !== false) { $string = preg_replace('/&((#(\d{3,5}|x[a-fA-F0-9]{4}));)/', '&\\1', $string); } } else { if (PHP_VERSION < '5.4.0') { $string = htmlspecialchars($string, $flags); } else { if (!defined('CHARSET') || (strtolower(CHARSET) == 'utf-8')) { $charset = 'UTF-8'; } else { $charset = 'ISO-8859-1'; } $string = htmlspecialchars($string, $flags, $charset); } } } return $string; } //------------------php防注入和XSS攻击通用过滤-----End--------------------------------------------//
PHP中的设置
PHP5.2以上版本已支持HttpOnly参数的设置，同样也支持全局的HttpOnly的设置，在php.ini中
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session.cookie_httponly =
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设置其值为1或者TRUE，来开启全局的Cookie的HttpOnly属性，当然也支持在代码中来开启：
<?php ini_set("session.cookie_httponly", 1); // or session_set_cookie_params(0, NULL, NULL, NULL, TRUE); ?>
Cookie操作函数setcookie函数和setrawcookie函数也专门添加了第7个参数来做为HttpOnly的选项，开启方法为：
<?php setcookie("abc", "test", NULL, NULL, NULL, NULL, TRUE); setrawcookie("abc", "test", NULL, NULL, NULL, NULL, TRUE); ?>
老版本的PHP就不说了。没企业用了吧。
