Terminal — Practice the Backup + Cron Skill
The most effective defensive technique at NCAE is a golden-config tarball + cron-every-60-seconds restore.
This emulator lets you practice it. The sandbox is a restricted in-browser shell that simulates a minimal Linux
filesystem with tar, crontab, ls, cat, echo,
systemctl (stubbed), and the five config directories the scoring engine cares about.
You can now create a golden-config tarball, install a 60-second restore cron, and verify it ran. This is the #1 defensive pattern used by 2022 national winners Illinois Tech and the 2025 3rd-place NJIT team.
What the real thing looks like
Once you have done the drill above, the real command you run at T+5 on your NCAE server is a 3-line recipe:
tar -czf /root/golden-configs.tar.gz /etc/ssh /etc/samba /etc/bind /etc/apache2 /etc/postgresql /etc/passwd /etc/shadow /etc/group /etc/sudoers
cat > /root/restore.sh <<'RESTORE_EOF'
#!/bin/bash
tar -xzf /root/golden-configs.tar.gz -C / 2>/dev/null
systemctl reload-or-restart sshd smbd named apache2 postgresql 2>/dev/null
RESTORE_EOF
chmod +x /root/restore.sh
(crontab -l 2>/dev/null; echo '* * * * * /root/restore.sh') | crontab -
Run this once at the start of competition, then forget about it. Red team edits a config; 60 seconds later, your restore script undoes it.
Sandbox scope
This terminal is a training sandbox, not a real shell. It simulates the minimum behavior needed to practice the backup-and-cron pattern. Real terminal behavior will differ. for real practice also SSH into one of your practice VMs or a Linux-based Docker container. The muscle memory of typing the commands in the right order is what this sandbox is for.