animatedcreativity · September 6, 2016 11:23 · Mar 9, 2016 · Mar 8, 2016 · Mar 8, 2016 · Mar 8, 2016
diff --git a/xss_clean.php b/xss_clean.php
@@ -26,17 +26,21 @@ class xssClean {
      */
     public function clean_input( $input, $safe_level = 0 ) {
 
+        $output = $input;
         do {
+            // Treat $input as buffer on each loop, faster than new var
+            $input = $output;
+
             // Remove unwanted tags
-            $old_input = $input;
             $output = $this->strip_tags( $input );
             $output = $this->strip_encoded_entities( $output );
 
+            // Use 2nd input param if not empty or '0'
             if ( $safe_level !== 0 ) {
                 $output = $this->strip_base64( $output );
             }
 
-        } while ( $output !== $old_input );
+        } while ( $output !== $input );
 
         return $output;
 

diff --git a/xss_clean.php b/xss_clean.php
@@ -58,7 +58,7 @@ private function strip_encoded_entities( $input ) {
         $input = html_entity_decode($input, ENT_COMPAT, 'UTF-8');
 
         // Remove any attribute starting with "on" or xmlns
-        $input = preg_replace('#(<[^>]+?[\x00-\x20"\'])(?:on|xmlns)[^>]*+[>\b]#iu', '$1>', $input);
+        $input = preg_replace('#(<[^>]+?[\x00-\x20"\'])(?:on|xmlns)[^>]*+[>\b]?#iu', '$1>', $input);
 
         // Remove javascript: and vbscript: protocols
         $input = preg_replace('#([a-z]*)[\x00-\x20]*=[\x00-\x20]*([`\'"]*)[\x00-\x20]*j[\x00-\x20]*a[\x00-\x20]*v[\x00-\x20]*a[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2nojavascript...', $input);

diff --git a/xss_clean.php b/xss_clean.php
@@ -58,7 +58,7 @@ private function strip_encoded_entities( $input ) {
         $input = html_entity_decode($input, ENT_COMPAT, 'UTF-8');
 
         // Remove any attribute starting with "on" or xmlns
-        $input = preg_replace('#(<[^>]+?[\x00-\x20"\'])(?:on|xmlns)[^>]*+>#iu', '$1>', $input);
+        $input = preg_replace('#(<[^>]+?[\x00-\x20"\'])(?:on|xmlns)[^>]*+[>\b]#iu', '$1>', $input);
 
         // Remove javascript: and vbscript: protocols
         $input = preg_replace('#([a-z]*)[\x00-\x20]*=[\x00-\x20]*([`\'"]*)[\x00-\x20]*j[\x00-\x20]*a[\x00-\x20]*v[\x00-\x20]*a[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2nojavascript...', $input);

diff --git a/xss_clean.php b/xss_clean.php
@@ -94,6 +94,10 @@ private function strip_tags( $input ) {
     /*
      * Focuses on stripping entities from Base64 encoded strings
      *
+     * NOT ENABLED by default!
+     * To enable 2nd param of clean_input() can be set to anything other than 0 or '0':
+     * ie: xssClean->clean_input( $input_string, 1 )
+     *
      * @param   string  $input      Maybe Base64 encoded string
      * @return  string  $output     Modified & re-encoded $input string
      */

diff --git a/xss_clean.php b/xss_clean.php
@@ -1,51 +1,113 @@
+<?php
 /*
- * XSS filter 
+ * XSS filter, recursively handles HTML tags & UTF encoding
+ * Optionally handles base64 encoding
+ *
+ * ***DEPRECATION RECOMMENDED*** Not updated or maintained since 2011
+ * A MAINTAINED & BETTER ALTERNATIVE => kses
+ * https://github.com/RichardVasquez/kses/
  *
  * This was built from numerous sources
  * (thanks all, sorry I didn't track to credit you)
- * 
+ *
  * It was tested against *most* exploits here: http://ha.ckers.org/xss.html
  * WARNING: Some weren't tested!!!
  * Those include the Actionscript and SSI samples, or any newer than Jan 2011
  *
- *
- * TO-DO: compare to SymphonyCMS filter:
- * https://github.com/symphonycms/xssfilter/blob/master/extension.driver.php
- * (Symphony's is probably faster than my hack)
  */
 
-function xss_clean($data)
-{
+class xssClean {
+
+    /*
+     * Recursive worker to strip risky elements
+     *
+     * @param   string  $input      Content to be cleaned. It MAY be modified in output
+     * @return  string  $output     Modified $input string
+     */
+    public function clean_input( $input, $safe_level = 0 ) {
+
+        do {
+            // Remove unwanted tags
+            $old_input = $input;
+            $output = $this->strip_tags( $input );
+            $output = $this->strip_encoded_entities( $output );
+
+            if ( $safe_level !== 0 ) {
+                $output = $this->strip_base64( $output );
+            }
+
+        } while ( $output !== $old_input );
+
+        return $output;
+
+    }
+
+    /*
+     * Focuses on stripping encoded entities
+     * *** This appears to be why people use this sample code. Unclear how well Kses does this ***
+     *
+     * @param   string  $input  Content to be cleaned. It MAY be modified in output
+     * @return  string  $input  Modified $input string
+     */
+    private function strip_encoded_entities( $input ) {
+
         // Fix &entity\n;
-        $data = str_replace(array('&amp;','&lt;','&gt;'), array('&amp;amp;','&amp;lt;','&amp;gt;'), $data);
-        $data = preg_replace('/(&#*\w+)[\x00-\x20]+;/u', '$1;', $data);
-        $data = preg_replace('/(&#x*[0-9A-F]+);*/iu', '$1;', $data);
-        $data = html_entity_decode($data, ENT_COMPAT, 'UTF-8');
+        $input = str_replace(array('&amp;','&lt;','&gt;'), array('&amp;amp;','&amp;lt;','&amp;gt;'), $input);
+        $input = preg_replace('/(&#*\w+)[\x00-\x20]+;/u', '$1;', $input);
+        $input = preg_replace('/(&#x*[0-9A-F]+);*/iu', '$1;', $input);
+        $input = html_entity_decode($input, ENT_COMPAT, 'UTF-8');
 
         // Remove any attribute starting with "on" or xmlns
-        $data = preg_replace('#(<[^>]+?[\x00-\x20"\'])(?:on|xmlns)[^>]*+>#iu', '$1>', $data);
+        $input = preg_replace('#(<[^>]+?[\x00-\x20"\'])(?:on|xmlns)[^>]*+>#iu', '$1>', $input);
 
         // Remove javascript: and vbscript: protocols
-        $data = preg_replace('#([a-z]*)[\x00-\x20]*=[\x00-\x20]*([`\'"]*)[\x00-\x20]*j[\x00-\x20]*a[\x00-\x20]*v[\x00-\x20]*a[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2nojavascript...', $data);
-        $data = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*v[\x00-\x20]*b[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2novbscript...', $data);
-        $data = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*-moz-binding[\x00-\x20]*:#u', '$1=$2nomozbinding...', $data);
+        $input = preg_replace('#([a-z]*)[\x00-\x20]*=[\x00-\x20]*([`\'"]*)[\x00-\x20]*j[\x00-\x20]*a[\x00-\x20]*v[\x00-\x20]*a[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2nojavascript...', $input);
+        $input = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*v[\x00-\x20]*b[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2novbscript...', $input);
+        $input = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*-moz-binding[\x00-\x20]*:#u', '$1=$2nomozbinding...', $input);
 
         // Only works in IE: <span style="width: expression(alert('Ping!'));"></span>
-        $data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?expression[\x00-\x20]*\([^>]*+>#i', '$1>', $data);
-        $data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?behaviour[\x00-\x20]*\([^>]*+>#i', '$1>', $data);
-        $data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:*[^>]*+>#iu', '$1>', $data);
-
-        // Remove namespaced elements (we do not need them)
-        $data = preg_replace('#</*\w+:\w[^>]*+>#i', '', $data);
-
-        do
-        {
-                // Remove really unwanted tags
-                $old_data = $data;
-                $data = preg_replace('#</*(?:applet|b(?:ase|gsound|link)|embed|frame(?:set)?|i(?:frame|layer)|l(?:ayer|ink)|meta|object|s(?:cript|tyle)|title|xml)[^>]*+>#i', '', $data);
-        }
-        while ($old_data !== $data);
-
-        // we are done...
-        return $data;
-}
+        $input = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?expression[\x00-\x20]*\([^>]*+>#i', '$1>', $input);
+        $input = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?behaviour[\x00-\x20]*\([^>]*+>#i', '$1>', $input);
+        $input = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:*[^>]*+>#iu', '$1>', $input);
+
+        return $input;
+
+    }
+
+    /*
+     * Focuses on stripping unencoded HTML tags & namespaces
+     *
+     * @param   string  $input  Content to be cleaned. It MAY be modified in output
+     * @return  string  $input  Modified $input string
+     */
+    private function strip_tags( $input ) {
+        // Remove tags
+        $input = preg_replace('#</*(?:applet|b(?:ase|gsound|link)|embed|frame(?:set)?|i(?:frame|layer)|l(?:ayer|ink)|meta|object|s(?:cript|tyle)|title|xml)[^>]*+>#i', '', $input);
+
+        // Remove namespaced elements
+        $input = preg_replace('#</*\w+:\w[^>]*+>#i', '', $input);
+
+        return $input;
+
+    }
+
+    /*
+     * Focuses on stripping entities from Base64 encoded strings
+     *
+     * @param   string  $input      Maybe Base64 encoded string
+     * @return  string  $output     Modified & re-encoded $input string
+     */
+    private function strip_base64( $input ) {
+
+        $decoded = base64_decode( $input );
+
+        $decoded = $this->strip_tags( $decoded );
+        $decoded = $this->strip_encoded_entities( $decoded );
+
+        $output = base64_encode( $decoded );
+
+        return $output;
+
+    }
+
+}
diff --git a/xss_clean.php b/xss_clean.php
@@ -7,6 +7,11 @@
  * It was tested against *most* exploits here: http://ha.ckers.org/xss.html
  * WARNING: Some weren't tested!!!
  * Those include the Actionscript and SSI samples, or any newer than Jan 2011
+ *
+ *
+ * TO-DO: compare to SymphonyCMS filter:
+ * https://github.com/symphonycms/xssfilter/blob/master/extension.driver.php
+ * (Symphony's is probably faster than my hack)
  */
 
 function xss_clean($data)

diff --git a/xss_clean.php b/xss_clean.php
@@ -0,0 +1,46 @@
+/*
+ * XSS filter 
+ *
+ * This was built from numerous sources
+ * (thanks all, sorry I didn't track to credit you)
+ * 
+ * It was tested against *most* exploits here: http://ha.ckers.org/xss.html
+ * WARNING: Some weren't tested!!!
+ * Those include the Actionscript and SSI samples, or any newer than Jan 2011
+ */
+
+function xss_clean($data)
+{
+        // Fix &entity\n;
+        $data = str_replace(array('&amp;','&lt;','&gt;'), array('&amp;amp;','&amp;lt;','&amp;gt;'), $data);
+        $data = preg_replace('/(&#*\w+)[\x00-\x20]+;/u', '$1;', $data);
+        $data = preg_replace('/(&#x*[0-9A-F]+);*/iu', '$1;', $data);
+        $data = html_entity_decode($data, ENT_COMPAT, 'UTF-8');
+
+        // Remove any attribute starting with "on" or xmlns
+        $data = preg_replace('#(<[^>]+?[\x00-\x20"\'])(?:on|xmlns)[^>]*+>#iu', '$1>', $data);
+
+        // Remove javascript: and vbscript: protocols
+        $data = preg_replace('#([a-z]*)[\x00-\x20]*=[\x00-\x20]*([`\'"]*)[\x00-\x20]*j[\x00-\x20]*a[\x00-\x20]*v[\x00-\x20]*a[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2nojavascript...', $data);
+        $data = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*v[\x00-\x20]*b[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2novbscript...', $data);
+        $data = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*-moz-binding[\x00-\x20]*:#u', '$1=$2nomozbinding...', $data);
+
+        // Only works in IE: <span style="width: expression(alert('Ping!'));"></span>
+        $data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?expression[\x00-\x20]*\([^>]*+>#i', '$1>', $data);
+        $data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?behaviour[\x00-\x20]*\([^>]*+>#i', '$1>', $data);
+        $data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:*[^>]*+>#iu', '$1>', $data);
+
+        // Remove namespaced elements (we do not need them)
+        $data = preg_replace('#</*\w+:\w[^>]*+>#i', '', $data);
+
+        do
+        {
+                // Remove really unwanted tags
+                $old_data = $data;
+                $data = preg_replace('#</*(?:applet|b(?:ase|gsound|link)|embed|frame(?:set)?|i(?:frame|layer)|l(?:ayer|ink)|meta|object|s(?:cript|tyle)|title|xml)[^>]*+>#i', '', $data);
+        }
+        while ($old_data !== $data);
+
+        // we are done...
+        return $data;
+}