About this CTF: https://www.seccon.jp/2019/akihabara/

I made black box programs called box. Can you find the input which follows my execution trace?

There are 4 boxes called attack-box and attached below. In other words, there are 4 problems (4 flags).

Submit your input to API /attack/<_id>/submit to get attack flag. An example sample-api-requestl.py attached below describes how to request.

There are 12 hourly rounds. Every round starts on xx:00. For example, round 1 starts on Day 1 11:00, and round 7 starts on Day 2 10:00.

A new box and a new execution trace are provided in every round through API /defense/latest.zip. Submit your input to API /defense/latest/submit. If your input passes server-side checks and if this is first correct submission in a round, challenge server writes your team's defense keyword into /defense/last/int/result (for international contest) or /defense/last/dom/result (for domestic contest).

Boxes in defense rounds are variant of attack-box's Box1.

• Server compares execution path of your input with original execution traces. You will get attack flag (or writes your team's defense keyword) if these are the same.
• NOTE: You MUST NOT attack the challenge server (including too frequent access and directory bruteforce).
• Location: http://follow-me-again-int.seccon/ (for international contest) or http://follow-me-again-dom.seccon/ (for domestic contest)
• Format of API request and response body are MessagePack or file stream.

• Attack-box: attack-box.zip
• Source code of tracer: branchtrace.cpp
• Sample script to call APIs: sample-api-request.py

Distributed fliles in the contest.

There's a solver for attack box1 and defense boxes. My solver uses Triton.