note 89453 deleted from function.strip-tags by aharvey

Note Submitter: nathan@8 ---- Improperly formatted javascript being add to tags and the limit of 15 instences of recursion before memory allocation runs out are some of the concerns involved in coding. Here is the code that I created to leave tags intact but strip scripting from only inside the tags... <?php function strip_javascript($filter){ // realign javascript href to onclick $filter = preg_replace("/href=(['\"]).*?javascript:(.*)? \\1/i", "onclick=' $2 '", $filter); //remove javascript from tags while( preg_match("/<(.*)?javascript.*?\(.*?((?>[^()]+) |(?R)).*?\)?\)(.*)?>/i", $filter)) $filter = preg_replace("/<(.*)?javascript.*?\(.*?((?> [^()]+)|(?R)).*?\)?\)(.*)?>/i", "<$1$3$4$5>", $filter); // dump expressions from contibuted content if(0) $filter = preg_replace("/:expression\(.*?((?>[^ (.*?)]+)|(?R)).*?\)\)/i", "", $filter); while( preg_match("/<(.*)?:expr.*?\(.*?((?>[^()]+)|(? R)).*?\)?\)(.*)?>/i", $filter)) $filter = preg_replace("/<(.*)?:expr.*?\(.*?((?>[^()] +)|(?R)).*?\)?\)(.*)?>/i", "<$1$3$4$5>", $filter); // remove all on* events while( preg_match("/<(.*)?\s?on.+?=?\s?.+?(['\"]).*?\\2 \s?(.*)?>/i", $filter) ) $filter = preg_replace("/<(.*)?\s?on.+?=?\s?.+? (['\"]).*?\\2\s?(.*)?>/i", "<$1$3>", $filter); return $filter; } ?> As you can see this does not clean up correctly... it does however remove dangerous stuff... <a href=javascript: { {({}{}()())}alert('xss') ) ) }> <div onload..;,;..'alert(\"xss_attack\");'> <a href='javascript:{ alert(\"xss_attack\"); otherxss();}' onclick= 'alert(\"xss_attack\");' onhover='alert (\"xss_attack\");' onmouseout=alert(\"xss_attack\") class='thisclass'> link</a> style='width:expression(alert(\"xss_attack\"));' This can be completed before using strip_tags().