How to exploit Liferay CVE-2020-7961 : quick journey to PoC

Liferay is one of the most known CMS written in Java that we encounter sometimes during assessment. Last week, we stumbled on the blog post from Code White Security entitled "Liferay Portal JSON Web Service RCE Vulnerabilities" describing an interesting issue. Unfortunately, there is no PoC associated with it, but as we love RCEs at Synacktiv, this is a good opportunity to learn something.

So, let's get started, here is a little tale on how to get a PoC, using marshalsec and the available researchs on the topic.