Arctic is fairly straightforward, however the load times on the web server pose a few challenges for exploitation. Basic troubleshooting is required to get the correct exploit functioning properly.

Optimum is a beginner-level machine which mainly focuses on enumeration of services with known exploits. Both exploits are easy to obtain and have associated Metasploit modules, making this machine fairly simple to complete.

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.

Legacy is a fairly straightforward beginner-level machine which demonstrates the potential security risks of SMB on Windows. Only one publicly available exploit is required to obtain administrator access.

Irked is a pretty simple and straight-forward box which requires basic enumeration skills. It shows the need to scan all ports on machines and to investigate any out of the place binaries found while enumerating a system.

Bashed is a fairly easy machine which focuses mainly on fuzzing and locating important files. As basic access to the crontab is restricted.

Shocker, while fairly simple overall, demonstrates the severity of the renowned Shellshock exploit, which affected millions of public-facing servers.