Hi everyone! I was tasked to create few challenges for a CTF at my university as part of my bachelor thesis. The last challenge I should create is essentially about crashing a system, while another "monitoring" system is detecting if the other one is running, and if not it gives you a flag. The tasks are meant for 4th year high-school students, so nothing insane, but this one still should be at an "extreme" difficulty in regard to the experience high-school students could have.

Issue is, I have no prior experience in such exploitation, and I don't necessarily know where to start with this one. My idea was creating a custom vulnerable module/driver in the linux kernel, that the players would be tasked to somehow exploit (some kind of overflow I guess, so that it would trigger kernel panic). I suppose it could be something similar to this: https://nofilqasim.info/Making%20a%20Kernel%20CTF%20%28PUCon%2724%20pwn%20CTF%29/ , except I believe the author of this CTF made it as a privilege escalation task, which is not exactly what I desire.

I was wondering if anyone could give me some pointers or ideas on where to start with this, and if what I have described above might be too difficult for the students to exploit, and consequently for me to implement.

Thank you for any answers!