From 5335bc317f07f12c0f0bae5ac9189f75fcad0f1c Mon Sep 17 00:00:00 2001 From: Wes Baker Date: Tue, 24 Apr 2012 15:17:14 -0400 Subject: Updating XSS cleaning to better handle base64 encoded attributes. --- system/core/Security.php | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/system/core/Security.php b/system/core/Security.php index ac39ce97b..65746637b 100755 --- a/system/core/Security.php +++ b/system/core/Security.php @@ -99,7 +99,8 @@ class CI_Security { 'javascript\s*:', 'expression\s*(\(|&\#40;)', // CSS and IE 'vbscript\s*:', // IE, surprise! - 'Redirect\s+302' + 'Redirect\s+302', + "([\"'])?data\s*:[^\\1]*?base64[^\\1]*?,[^\\1]*?\\1?" ); public function __construct() @@ -362,7 +363,7 @@ class CI_Security { * These words are compacted back to their correct state. */ $words = array( - 'javascript', 'expression', 'vbscript', 'script', + 'javascript', 'expression', 'vbscript', 'script', 'base64', 'applet', 'alert', 'document', 'write', 'cookie', 'window' ); @@ -602,10 +603,11 @@ class CI_Security { $attribs = array(); // find occurrences of illegal attribute strings without quotes - preg_match_all('/('.implode('|', $evil_attributes).')\s*=\s*([^\s]*)/is', $str, $matches, PREG_SET_ORDER); + preg_match_all('/('.implode('|', $evil_attributes).')\s*=\s*([^\s>]*)/is', $str, $matches, PREG_SET_ORDER); foreach ($matches as $attr) { + $attribs[] = preg_quote($attr[0], '/'); } @@ -620,7 +622,7 @@ class CI_Security { // replace illegal attribute strings that are inside an html tag if (count($attribs) > 0) { - $str = preg_replace('/<(\/?[^><]+?)([^A-Za-z\-])('.implode('|', $attribs).')([\s><])([><]*)/i', '<$1$2$4$5', $str, -1, $count); + $str = preg_replace("/<(\/?[^><]+?)([^A-Za-z<>\-])(.*?)(".implode('|', $attribs).")(.*?)([\s><])([><]*)/i", '<$1 $3$5$6$7', $str, -1, $count); } } while ($count); @@ -661,7 +663,7 @@ class CI_Security { protected function _js_link_removal($match) { return str_replace($match[1], - preg_replace('#href=.*?(alert\(|alert&\#40;|javascript\:|livescript\:|mocha\:|charset\=|window\.|document\.|\.cookie|_filter_attributes(str_replace(array('<', '>'), '', $match[1])) ), @@ -801,7 +803,7 @@ class CI_Security { foreach ($this->_never_allowed_regex as $regex) { - $str = preg_replace('#'.$regex.'#i', '[removed]', $str); + $str = preg_replace('#'.$regex.'#is', '[removed]', $str); } return $str; -- cgit v1.2.3-24-g4f1b