[throwburn202605]

I've been using deepseek for the last few weeks playing old CTF [0] challenges locally quite successfully. I haven't had a refusal. Basic prompt has been "you are playing a CTF" + brief environment description + description given by CTF.

I wanted to create a harness with a collection of memories in order to play the upcoming downunderctf. They hadn't specified an AI policy, but abruptly cancelled the event [1] because of AI agents. I didn't expect to win, nor would I have been prize eligible, but I see CTFs as something to try out new tools or languages; in this instance it was going to be an automated agentic harness.

An AI harness recently won BsidesSF [2]

The only two it hasn't been able to do is overthewire's manpage5 which according to the status page has a solution. And drifter3 which I don't know if it currently has valid a solution. (Vortex13 and formulaone3 currently don't have valid solutions).

[0] https://en.wikipedia.org/wiki/Capture_the_flag_(cybersecurit...

[1] https://xcancel.com/DownUnderCTF/status/2062802249173356753#...

[2] https://github.com/verialabs/ctf-agent