Attack a live Linux target in your browser
Every session is a new host, new story, new puzzle. No walkthroughs exist because no two runs are the same.
No signup · 15-minute demo · Beginner-friendly
root@webserver-04a:~# nmap -sV 10.0.8.0/24
Starting Nmap 7.94 ( https://nmap.org )
Nmap scan report for 10.0.8.3
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 8.9p1
80/tcp open http Apache 2.4.52
3306/tcp open mysql MySQL 5.7.38
root@webserver-04a:~# ls -la /var/www/html/
drwxr-xr-x 4 www-data www-data 4096 Apr 7 09:12 .
-rw-r--r-- 1 www-data www-data 814 Apr 7 09:12 index.php
-rw-r----- 1 root root 42 Apr 7 08:55 .db_creds
root@webserver-04a:~# cat .db_creds
cat: .db_creds: Permission denied
Powered by 149,000+ real attack events captured across 6 global nodes
Every Session is Different
No two environments are the same. The host, filesystem, processes, and story change every time you connect.
Walkthrough-Proof
No guide can help because the scenario changes every run. You develop real methodology, not memorised steps.
Real Attack Intelligence
Scenarios are informed by genuine threat data from global monitoring. Train against patterns that matter.
How It Works
Step 1
Enter a live terminal
Connect to a real Linux environment directly in your browser. No installs, no VPN, no setup.
Step 2
Investigate the host
Enumerate services, explore the filesystem, read logs, and piece together what happened on this machine.
Step 3
Capture objectives and score
Find the flags, complete the objectives, and earn a score based on your technique and efficiency.
Why this isn't another static CTF
Traditional capture-the-flag platforms give everyone the same box. Once someone writes a walkthrough, the challenge is dead.
Static CTFs
- Fixed host every time
- Known process tree
- Reusable walkthroughs
- Same experience every session
Krystal Arena
- New host each run
- Variable processes
- No walkthrough fits
- Different every session
Coming Soon
DAEMON Mode
Can you root a box that's fighting back?
An adaptive defender watches your every command. Taunts you. Moves files. Rotates credentials. Good luck.
Pricing
Pro
$14.99/mo
or $99/year
- All scenarios
- Unlimited sessions
- DAEMON mode
- Leaderboard
- Badges
Your next scenario hasn't been created yet.
It will be when you start it.