ctf-writeup/2023/MHSCTF 2023/Feb. 3 - Flowers

Feb. 3 - Flowers

Another Valentine classic... flowers! Flowers can be expensive, so I bought a bunch of them cheap online. Turns out they're infested with some kind of bug and I need to buy a specialized pesticide to take care of them. The pesticide is really expensive, but the online seller is willing to give me a discount code if I can analyze a program he gives me. As I said, I'm nine years old sooooooooooo... do it for me? Enter your answers at the given link.

About the Challenge

We were given a website to submit the number and some weird file named flowers.fish.txt and need to find the flag on it.

How to Solve?

If we open the file, the file will be looks like this

And then one of the team member said this chall using esolangs website. Because the file named flowers.fish.txt, I suspect that this code uses the Fish language. And then i tried to run the program using "official" interpreter and then I got some number

I created some python code to run the program 1000 times and then get the average number of times the program will produce outputs. The code will be looks like this

import subprocess

def count_digits(numbers):
    count = {}
    for number in numbers:
        for digit in str(number):
            if digit in count:
                count[digit] += 1
            else:
                count[digit] = 1
    return count

results = []
for i in range(1000):
    output = subprocess.run(["python3", "fish.py", "flowers.fish"], capture_output=True, text=True)
    results.append(output.stdout)

print(dict(sorted(count_digits(results).items())))

After obtaining output from the program I wrote earlier, I will input it into the submission portal and then I receive the flag

valentine{fly1n9_purp13_p3t4l_e4ter5}