CSCD 240 · Spring 2026

Capture The Flag

Hands-on challenges that test your Unix, C, and systems skills. Read the prompt, solve the problem, submit the flag. No prior CTF experience needed.

Week 2 CTF

LABS 1-4 114 challenges · 2,245 pts total

Tests the material from Labs 1-4 (Navigation, Pathnames, Permissions, Redirection & Environment) and lectures 1-8. Start with the Enter the Password challenge - only given in class (or arranged with Stu ahead of time).

Section # Pts Source
Navigation & Files 20 260 Labs 1-2 · Lectures 1-6
Shell & Help 12 220 Lab 2 · Lectures 2-5, 7
Permissions 14 260 Lab 3 · Lectures 3, 5-6
I/O & Pipelines 13 175 Lab 4 · Lectures 3, 6, 8
Environment & Patterns 16 250 Lab 4 · Lectures 7-8
SSH: Hands-On Practice 21 565 Labs 1-4 applied on live server
BONUS: Lecture Recall 18 515 Stretch - lecture-only, locked until you solve one from each main category
Total 114 2,245

Getting "REMOTE HOST IDENTIFICATION HAS CHANGED"?

The challenge SSH server was recently rebuilt with a new host key. If you connected during the practice CTF, your machine remembers the old key and will refuse to connect. Run this command first, then try again:

$ ssh-keygen -R "[play.jdoner.me]:2222"

Then reconnect with your SSH command. You'll be prompted to accept the new key - type yes.

What is a CTF?

A guided technical puzzle. In this class, it means using Unix, terminal, and systems skills you practice in labs to find and submit answers.

Why CTFs?

Apply course concepts in a concrete, active way. They are meant to feel hands-on and a little playful, not intimidating.

Privacy first

The leaderboard is anonymous. Use your course handle instead of your real name so the scoreboard stays FERPA-safe.

1

Sign in

Use the GitHub account from the start of the course.

2

Open a challenge

Read the prompt. Some are direct answers, some require terminal work.

3

Find the flag

Submit the answer — often FLAG{...} or a plain value.

4

Keep going

Wrong answers cost nothing. Experiment freely.

Event Schedule Spring 2026
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Grading: each CTF is worth 1 Canvas point. Earn 70%+ of the CTFd points for full credit. Below 70% = no credit. No partial credit.

Credit threshold
≥70%
Full Credit
<70%
No Credit
Live events happen in class on Fridays, 9:00–9:50 AM. Practice sets open earlier in the week so you can prepare.

Sign in with the GitHub account you created for this course. That identity link is how CTF scores map back to Canvas.

Do not share flags or screenshots during a live event. Use your own handle. Academic honesty applies here.

Canvas is the source of truth for grading and event names: Week 1 CTF, Week 2 CTF, etc.

Brand new to this? Start with Getting Started for a step-by-step walkthrough of flags and submissions.