Machine Synopsis

OneTwoSeven is a hard difficulty Linux box which provides users with SFTP access. The SFTP shell allows for creating symlinks, which can be abused to gain access to the administrative panel. The admin panel has a restricted upload imposed by Apache rewrite rules. These can be bypassed to upload a php shell. The www user has permissions to upgrade local packages, but due to a misconfiguration, a proxy server can be used to install a malicious package to execute code as root.