Silo focuses mainly on leveraging Oracle to obtain a shell and escalate privileges. It was intended to be completed manually using various tools, however Oracle Database Attack Tool greatly simplifies the process, reducing the difficulty of the machine substantially.

Grandpa is one of the simpler machines on Hack The Box, however it covers the widely-exploited CVE-2017-7269. This vulnerability is trivial to exploit and granted immediate access to thousands of IIS servers around the globe when it became public knowledge.

Granny, while similar to Grandpa, can be exploited using several different methods. The intended method of solving this machine is the widely-known Webdav upload vulnerability.

Blue, while possibly the most simple machine on Hack The Box, demonstrates the severity of the EternalBlue exploit, which has been used in multiple large-scale ransomware and crypto-mining attacks since it was leaked publicly.

Sunday is a fairly simple machine, however it uses fairly old software and can be a bit unpredictable at times. It mainly focuses on exploiting the Finger service as well as the use of weak credentials.