Jarvis is a medium difficulty Linux box running a web server, which has DoS and brute force protection enabled. A page is found to be vulnerable to SQL injection, which requires manual exploitation. This service allows the writing of a shell to the web root for the foothold. The www user is allowed to execute a script as another user, and the script is vulnerable to command injection. On further enumeration, systemctl is found to have the SUID bit set, which is leveraged to gain a root shell.

FriendZone is an easy difficulty Linux box which needs fair amount enumeration. By doing a zone transfer vhosts are discovered. There are open shares on samba which provides credentials for an admin panel. From there, an LFI is found which is leveraged to get RCE. A cron is found running which uses a writable module, making it vulnerable to hijacking.

TartarSauce is a fairly challenging box that highlights the importance of a broad remote enumeration instead of focusing on obvious but potentially less fruitful attack vectors. It features a quite realistic privilege escalation requiring abuses of the tar command. Attention to detail when reviewing tool output is beneficial when attempting this machine.

Valentine is a very unique medium difficulty machine which focuses on the Heartbleed vulnerability, which had devastating impact on systems across the globe.