An interesting box sitting on the ELK (ElasticSearch, Logstash & Kibana) stack with a slant for the CTF side, but a very good introduction to those technologies.
Despite the “Easy” tag, La Casa de Papel was an elaborate box. A vulnerable service leads to an unusual, limited PHP shell which allows us to generate our own signed certificates to access a specific part of the site. From there, a local file inclusion lets us acquire SSH credentials and then escalate to root via a misconfiguration.
A fairly straightforward machine, Lightweight lets us explore an insuficiently secured LDAP environment, where we intercept credentials by listening in to the network device. It also leads down the path of Linux capabilities, to find an openssl binary which can do far more than it should.