Application Security London - Vulnerability Research

Archive

Compromising Plesk via its REST API

Plesk is a commercial web hosting and server data center automation software developed for Linux and Windows-based retail hosting service providers. It’s the main choice of web hosting providers these days being used by 86.7% of the websites that use a web panel for administration. This is 4.4% of all websites and there around 2M Plesk installations in the US alone. As expected there are many interesting features to attack as an administrator, however we couldn’t find anything really exploitable and also it isn’t that interesting to begin with, if you’re already an administrator, right? We tried to see if we can escalate our privileges from one of the limited roles, but these seem solid. In the end we discovered a cookieless CSRF, which is basically a design issue in this case, because it affects all the POST requests and we could abuse most of the APIs with it.

Multiple vulnerabilities in Concrete CMS – part2 (PrivEsc/SSRF/etc)

We have previously wrote about Concrete CMS here. In that post we described how we managed to exploit a double race condition vulnerability in the file upload functionality in order to obtain remote command execution. In this blog post we will present multiple vulnerabilities in Concrete CMS that we have found at the end of last year during a pentest for one of our customers. For more info please see the “Mitigations” section regarding security tips for fixing the password poisoning issue and other tips on improving security for Concrete CMS.

Multiple Concrete CMS vulnerabilities ( part1 – RCE )

Concrete CMS is designed for ease of use, for users with a minimum of technical skills. It enables users to edit site content directly from the page. It provides  version management for every page, similar to wiki software, another type of web site development software. Concrete5 allows users to edit images through an embedded editor on the page. As of 2021, there are over 62,000 live websites that use Concrete CMS under the hood. During a recent pentest, our team found a very interesting vulnerability. Discovery of the vulnerability was relatively simple (a race condition), however creating a POC was quite challenging, hence the reason for this post. You will need a low privileged user to exploit this vulnerability and gain RCE in Concrete CMS.

Independently secure, together not so much – a story of 2 WP plugins

Recently we had to do a security assessment on a WordPress website. Obviously when dealing with a WordPress installation the best option is to always target the plugins. We’ve quickly enumerated the plugins using WPScan and then we recreated this setup in our local environment for easier testing & debugging. We found 2 interesting plugins which support file uploads and that is always interesting functionality to abuse, so we will study them one by one.

Multiple vulnerabilities in cPanel/WHM

cPanel is a web hosting control panel software developed by cPanel, LLC. It provides a graphical interface (GUI) and automation tools designed to simplify the process of hosting a web site to the website owner or the “end user”. It enables administration through a standard web browser using a three-tier structure. While cPanel is limited to managing a single hosting account, cPanel & WHM allows the administration of the entire server. Our team has found multiple vulnerabilities in cPanel/WHM during a black-box pentest, the most important ones being an RCE and privilege escalation via stored XSS.