A Capture-the-Flag (CTF) Exercise Explained

A capture-the-flag (CTF) exercise is a simulated cybersecurity competition that challenges participants to find and exploit vulnerabilities in a computer system in order to ‘capture a flag’. The ‘flag’ may be a specific piece of data or code hidden within the system. Participants will rehearse working seamlessly together, and they may need to use a variety of skills and techniques. The teams may also need to defend their own systems against attacks.

The goal of a capture-the-flag exercise is to provide a realistic and challenging cybersecurity experience that helps participants to develop and refine their skills in a controlled environment.

CTF exercises typically involve multiple teams, each consisting of several participants, who compete against each other to capture as many flags as possible within a specified time period.

The teams are given a set of objectives and rules at the beginning of the exercise, and must work together to devise and execute a strategy for finding and capturing the flags.

Podium view
The podium view presents the participant the final scores and overview of each team’s results. The number of tasks available is configurable and is the main mean on defending the length and complexity of the training event.

The role of the instructor in a CTF exercise is to oversee the competition, monitor the progress of the teams, and ensure that the exercise is conducted safely and ethically. The instructor may also provide guidance and assistance to the teams as needed, and may adjust the difficulty of the exercise to ensure that it is appropriately challenging for the participants.

The participating teams must work together to identify and exploit vulnerabilities in the system, and they may need to use a variety of skills and techniques, such as network analysis, reverse engineering, and cryptography.

The teams may also need to defend their own systems against attacks from other teams, and must maintain good communication and coordination in order to be successful.

Mission board
The mission board presents the participant an overview of the progress of the event. The participant can see which tasks are solved, on hold, open, or locked.

Process-wise, let us go through the steps in a typical CTF exercise:

  1. Planning and Preparation: The exercise organizers and instructors develop the scenario and objectives for the CTF, create the virtual environment, and set up the necessary tools and resources for the participants. This may involve selecting a theme or scenario for the exercise, designing the systems to be attacked and defended, and creating the flags that the teams will need to capture.
  2. Kickoff and Rules: The organizers will then hold a kickoff event to introduce the exercise to the participants and provide them with the rules, objectives, and guidelines. This may include a briefing on the scenario, an overview of the virtual environment, and instructions on how to access the tools and resources.
  3. Reconnaissance: The teams begin to explore and analyze the virtual environment in order to identify vulnerabilities and potential attack vectors. This may involve performing network scans, analyzing system configurations, and gathering information on other teams.
  4. Exploitation: Once the teams have identified potential vulnerabilities, they begin to develop and execute strategies for exploiting them. This may involve launching attacks, deploying malware, or manipulating data in order to gain access to systems and capture flags.
  5. Defense: As the exercise progresses, teams may also need to defend their own systems against attacks from other teams. This may involve monitoring network traffic, analyzing logs, and implementing defensive measures such as firewalls and intrusion detection systems.
  6. Scoring and Evaluation: Throughout the exercise, the organizers and instructors track the progress of the teams and score their performance based on the number of flags captured and other criteria. At the end of the exercise, the scores are tallied and the winners are announced.
  7. Debriefing: After the exercise is complete, the organizers and instructors typically hold a debriefing session with the participants to review their performance, provide feedback on their strategies and techniques, and offer insights into the vulnerabilities and attacks used in the exercise. This helps the participants to learn from their experiences and improve their skills for future cybersecurity challenges.