CSCTF 2026
Dynamic Flags
Some challenges use flags that rotate every 5 minutes on the clock boundary (:00, :05, :10, ...). Retrieve and submit within the same window.
- A flag retrieved at 16:04:58 and submitted at 16:05:02 is already invalid.
- Never cache a flag between attempts. Always retrieve fresh, immediately before submitting.
- Script the retrieval. Manual steps are too slow for a 5-minute window.
- Dynamic flags are per-team. Do not share them.
If a flag seems correct but is rejected, re-retrieve immediately. If the problem persists, report it in Discord with the challenge name and the time of your attempt.