CTFd Docker Plugin

This plugin for CTFd allows competing teams/users to start dockerized images for presented challenges. It adds a challenge type "docker" that can be assigned a specific docker image/tag.

For Contributors: See CONTRIBUTING.md for development setup, code quality standards, and contribution guidelines.

Version 4.0.4

Latest Update: Migrated to Alpine.js and Bootstrap 5 for CTFd 3.8.0+ (core theme)

Requirements

• CTFd 3.8.0+ (includes core theme with Alpine.js and Bootstrap 5)
• Python 3.x with flask_wtf installed (pip install flask_wtf)
• Docker API accessible via HTTP or TLS
• Modern Browser: Chrome 90+, Firefox 88+, Safari 14+, Edge 90+ (IE11 not supported)

Key Features

• Allows players to create their own docker container for docker challenges
• Configurable exposed ports with auto-population from Docker images
• 5 minute revert timer with self-correcting countdown
• 2 hour stale container auto-cleanup
• Status panel for Admins to manage active containers
• Support for TLS docker API connections with client certificate validation (HIGHLY RECOMMENDED)
• Docker container auto-cleanup on solve
• Seamless integration with CTFd core theme
• Content Security Policy (CSP) compliant - no inline JavaScript

Configuration Requirements

• Docker Config must be set first via /admin/docker_config
• Currently supported: plain HTTP (no encryption) or full TLS with client certificate validation
• TLS configuration guide: https://docs.docker.com/engine/security/https/
• Challenges stored by repository tags (e.g., stormctf/infosecon2019:arbit)

Migration from v2.x

Migration summary:

• v3.0.0 requires CTFd 3.8.0+ (core theme)
• No database changes - existing challenges work without modification
• Frontend modernized with Alpine.js + Bootstrap 5
• All features maintain functional parity with v2.x
• Known fixes: Dynamic form loading, ExposedPorts handling for images without ports

Important Notes

• Using the same Docker tag for multiple challenges may cause issues - not fully tested
• Security test your installation before production use
• CTFd 2.3.3 required get_configurable_plugins modification (Fixed in CTFd 3.2.1+)
• Active containers continue running during plugin upgrades/downgrades

Installation / Configuration

Quick Start

1. Install CTFd 3.8.0+

   cd CTFd
   git checkout 3.8.0  # or later

2. Install Plugin

   # Clone into plugins directory
   git clone https://github.com/shiftysheep/CTFd-Docker-Challenges.git CTFd/CTFd/plugins/docker_challenges
   
   # Install Python dependencies
   pip install flask_wtf

3. Restart CTFd

   # Docker Compose
   docker-compose restart ctfd
   
   # Or manual restart
   python3 serve.py

4. Configure Docker API

   • Navigate to /admin/docker_config
   • Add Docker API connection details (hostname:port)
   • Enable TLS if using secure connection (recommended)
   • Select repositories containing challenge images
   • Click Submit

5. Create Docker Challenges

   • Go to Challenges → Create Challenge
   • Select docker or docker_service as challenge type
   • Choose Docker image from dropdown (sorted alphabetically)
   • Configure challenge as normal (name, description, flags, etc.)
   • Click Submit

6. Verify Functionality

   • View challenge as user
   • Click "Start Docker Instance"
   • Verify countdown timer displays (5:00 → 4:59 → ...)
   • Verify connection details show (Host: X.X.X.X Port: XXXXX)
   • Test revert functionality after timer expires

Contributing

Interested in contributing? See CONTRIBUTING.md for:

• Development environment setup
• Code quality standards and pre-commit hooks
• Commit message conventions
• Testing guidelines
• Pull request process

Release History

See CHANGELOG.md for detailed version history and release notes.

Credits

• https://github.com/offsecginger (Twitter: @offsec_ginger)
• Jaime Geiger (For Original Plugin assistance) (Twitter: @jgeigerm)