Black Hills Infosec Webcast CTF

Each week, our Weekly CTF (Capture The Flag) competition gives you a fresh, interactive challenge designed to test and expand your cybersecurity skills in a fun, competitive environment.

What makes our CTF unique?
We build every challenge around scenarios developed from Backdoors & Breaches cards, the incident response card game created by Black Hills Information Security.

Participants who complete the submission form below will be entered in a giveaway for free training from Antisyphon Training and participants who complete their submission form will be entered to receive a one-of-a-kind BHIS CTF challenge t-shirt.

Winners will be chosen on the following Monday of every webcast. You have approximately 3 days to submit your answers.

Click Here to Join the CTF

This Week’s Challenge: Filtered Reality

This week’s Weekly CTF is built around the Backdoors & Breaches scenario Initial Compromise: External Service Exploitation.

Filtered Reality drops you into a tightly controlled execution environment that claims to be secure thanks to strict filtering rules. The system allows limited input and promises that anything dangerous has already been blocked.

Your goal is to question that assumption.

This challenge focuses on understanding how input validation works, how programming languages actually interpret user input, and where defensive assumptions can break down. Success requires thinking beyond what is explicitly blocked and recognizing how data can change as it moves through different stages of processing.

It is a lesson in why blacklists are fragile, why surface level defenses are risky, and how attackers look for gaps between what defenders expect and what systems actually do.

Difficulty is moderate and rewards careful observation, language knowledge, and creative thinking rather than brute force.

Ready to jump in and test your skills?
👉 Learn more about Backdoors & Breaches: https://www.blackhillsinfosec.com/tools/backdoorsandbreaches/