Capture The Flags / Write-Ups / osu!gaming CTF 2025 / lunatic-ksm

There's a reason why the term "illegal pattern" exists.

発狂KSM os/us難易度表 (v5.0)

Make sure to submit flag content in uppercase, like this: osu{HELLO_WORLD}

Downloads
rhythm_lunatic-ksh.tar.gz

The zip contains a K-Shoot Mania chart.

• If we search up impossible patterns in KSM, we'll find this page from the Sound Voltex wiki.
• The page has a link to this Google Drive with files for all insane KSM maps.
• Navigate to the map corresponding to the map from the challenge.

Compare 4_in.ksh in the drive with the 4_in.ksh from the challenge:

• We'll find that the challenge map has extra content near the end.

• Using a ksm beatmap viewer like viewksm.dev or kshoot-tools, we can find out what's at the end of the map.


Using kshoot-tools:
kshoot 4_in.ksh render -m=171 --pulses_per_column=7000 -c=1

• The chart spells out the flag.
osu{KONASUTE_IS_A_SCAM}

Thus, we acquired the flag for rhythm/lunatic-ksm.

Flag: osu{KONASUTE_IS_A_SCAM}