CSCD 240 — Week 2 CTF
Test your Labs 1–4 skills · Leaderboard for bragging rights · No grade impact
How to Play
- Register an account (top right) and log in.
- Go to Challenges and unlock Enter the Password first — your instructor announced the password in class and on Discord.
- Work through the challenges. Each one accepts either the raw answer or
FLAG{answer}format. - Watch your rank on the Scoreboard.
Point Breakdown
| Section | Challenges | Points | Source |
|---|---|---|---|
| 00 — Navigation & Files | 20 | 260 | Labs 1–2 |
| 01 — Shell & Help | 12 | 220 | Lab 2 + Lectures 2–5 |
| 02 — Permissions | 14 | 260 | Lab 3 + Lectures 3, 5, 6 |
| 03 — I/O & Pipelines | 13 | 175 | Lab 4 + Lectures 3, 6, 8 |
| 04 — Environment & Patterns | 16 | 250 | Lab 4 + Lectures 7, 8 |
| 05–10 — SSH: Hands-On | 21 | 565 | Labs 1–4 applied on live server |
| 99 — BONUS: Lecture Recall | 18 | 515 | Stretch — mentioned in lectures (locked until you solve one from each main category) |
| TOTAL | 114 | 2,245 |
SSH Connection Trouble?
Some challenges ask you to SSH into play.jdoner.me. If you get this error:
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@Fix it by running this command first:
ssh-keygen -R "[play.jdoner.me]:2222"Then try your SSH command again. You'll be asked to accept the new host key — type yes.
Why does this happen? The challenge server was rebuilt recently. Your local machine remembers the old host's fingerprint and SSH protects you by refusing to connect until you confirm the change is expected.
Rules
- Play fair — no sharing flags, no brute-forcing the submission form.
- Each SSH connection gets an isolated container. Your changes only affect you.
- Do NOT attempt to escalate privileges or attack the infrastructure.
- Session idle timeout: 10 minutes.
- Stuck? Buy a hint (deducts from challenge points) or ask in class.
Questions? Email ctf@jdoner.me · Good luck and have fun!