Machine Synopsis

Registry is a hard difficulty Linux machine, which features Docker and the Bolt CMS running on Nginx. Docker registry API access is configured with default credentials, which allows us to pull the repository files. Using the disclosed information it is possible to obtain an initial foothold. User credentials for Bolt CMS can be obtained, and exploiting the CMS provides us with access to the `www-data` user, who has a sudo entry to perform backups as root using the `restic` program. After taking a backup of the root folder remotely and mounting the repository with restic, the root flag is obtained.