Updown is a really challenging machine very focused on niche web exploitation, solid code review and careful parameter manipulation to actually exploit the attack vectors.
Sauna is an interesting machine. It goes through a relatively straight-forwards attack path but I fell into a number of false assumptions and rabbit-holes which costed me a lot of time. It’s serves as a great reminder to perform a full enumeration before jumping into any conclusions, to leave no stone upturned and to pay attention to small details.
Escape is a great machine covering basic network enumeration, intermediate knowledge about MSSQL attack vectors and escalation with ADCS. It doesn’t show any niche techniques or obscure vulnerabilities but provides some great fundamental challenges with a seamless and intuitive attack path.
Craft is a challenging box focused on API abuse, code review, and exploitation of insecure application logic. It required careful analysis of a vulnerable API, understanding how user input flows through the system, and leveraging injection techniques to achieve code execution. It was a tough one for sure, but very much worth it.
Authority is an interesting take on Windows and Active Directory attacks, it demonstrates a mix of known techniques and a niche pathways that I was not familiar with. It took a seemengly trivial AD privilege escalation and introduced a number of fun challenges that made the box interesting at each part of completion.