While poking around Parallels Desktop I found a script which is invoked by a setuid-root binary, which has the following snippet: local prl_dir="${usr_home}/Library/Parallels" if [ -e "$prl_dir" -a ! -d "$prl_dir" ]; then log warning "'${prl_dir}' is not a directory. Renaming it." mv -f "$prl_dir"{,~} continue fi Here ${usr_home} represents the home directory of the user for which Parallels Desktop is installed. The code says if ~/Library/Parallels exists and is not a directory then move it to ~/Library/Parallels~, presumably to back it up before creating this path as a directory.

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.