The Schooled HackTheBox machine is a Medium FreeBSD system with a Moodle web content manager, very real-life applicable as many school and university systems are configured the same way as this one. From a simple school webpage, you go through student, teacher and manager accounts to finally root the system.
autoUniCalendar is a script which converts the Uniovi calendar into Google and Microsoft calendars by reading the HTTP requests to the web server, and parsing the calendar data into a CSV file readable by every calendar application.
The Knife machine of HackTheBox is an easy Linux machine very useful to understand basic concepts about enumeration, and how to stablish a simple reverse shell. It is also helpful to understand the escalation of privileges using GTFObins.
Love is a very easy Windows machine that can be easily solved if some basic concepts are clear. It contains a SSRF attack, which is not very common, and this machine is a very good example of how it works. Enumeration is also very important here, for both foothold and privilege escalation, this last one taking advantage of the AlwaysInstallElevated feature being turned on.
Academy is a very complete Linux machine about the new HackTheBox Academy platform, which covers enumeration with directory lists, virtual hosting, Laravel exploitation, a lot of lateral movement and privilege escalation with composer.
Tabby is an easy and enjoyable Linux machine with an LFI to get the foothold, user pivoting from tomcat and an abuse of the lxd group privilege.
Remote is a Windows machine with the Umbraco web content manager, which is exploited through a mountable partition and cached credentials whose greatest vulnerability is an outdated version of Umbraco, what makes possible to exploit the machine.
Sauna is a very complete Windows machine, in which some of the most common tools are used to gain access and escalate privileges in the system. The enumeration requires making a list of possible usernames using the about page of the website. In the privilege escalation, the Pass-The-Hash technique is used to become administrator, which makes the machine interesting at the same time that it is easy and enjoyable to start with Windows pentesting.