The goal of this blog post is to present a privilege escalation I found while working on ADCS. We will see how it is possible to elevate our privileges to NT AUTHORITY\SYSTEM from virtual and network service accounts of a domain-joined machine (for example from a webshell on a Windows server) using ADCS. I want to call this attack chain “CertPotato” as homage to other *Potato tools and as a way to better remember it.

A popular technique for getting SYSTEM from a virtual or network service account is Delegate 2 Thyself by Charlie Clark. This technique involves using RBCD to elevate your privileges. In this article, I propose an alternative approach to become local SYSTEM using ADCS.