Application Security London - Vulnerability Research


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.