ターゲット // Fail
PlatformOffSec Proving Grounds
OSLinux
DifficultyMedium
IP192.168.100.126

Enumeration

Nmap

▶ Nmap output
PORT    STATE SERVICE VERSION
22/tcp  open  ssh     OpenSSH 7.9p1 Debian 10+deb10u2 (protocol 2.0)
873/tcp open  rsync   (protocol version 31)

Two ports. SSH accepts both pubkey and password auth but we have no creds, so it stays shut for now. That leaves rsync on 873 – a daemon that ships wide open more often than it should.