picoCTF 2019 mus1c Writeup

Music is a General Skills puzzle worth 300 points.

Description

I wrote you a song. Put it in the picoCTF{} flag format.

This puzzle provides lyrics.txt, which is as follows:

Pico's a CTFFFFFFF
my mind is waitin
It's waitin

Put my mind of Pico into This
my flag is not found
put This into my flag
put my flag into Pico


shout Pico
shout Pico
shout Pico

My song's something
put Pico into This

Knock This down, down, down
put This into CTF

shout CTF
my lyric is nothing
Put This without my song into my lyric
Knock my lyric down, down, down

shout my lyric

Put my lyric into This
Put my song with This into my lyric
Knock my lyric down

shout my lyric

Build my lyric up, up ,up

shout my lyric
shout Pico
shout It

Pico CTF is fun
security is important
Fun is fun
Put security with fun into Pico CTF
Build Fun up
shout fun times Pico CTF
put fun times Pico CTF into my song

build it up

shout it
shout it

build it up, up
shout it
shout Pico

Solution

I would have had a hard time with this puzzle, however I knew that this was a program written in the Rockstar programming language because I watched The Art of Code a couple of months ago after hasherezade linked it on Twitter.

If you have about an hour to kill, I thought this was a very entertaining talk.

Rockstar has an online interpreter here. Pasting the lyrics into this interpreter and clicking on Rock! yields several numbers as output:

These looked like Charcodes, so I put this into CyberChef and decoded the flag:

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