public@themctf:~$

MOOOO

I really like Cows

misc2025
views
-
writeup by
pavel?!
published
09 November 2025

SOLVE NOTES

Original on GitHub

Challenge

I Ire given a single JPEG file named MOOOO.jpeg along with a short description.
The title and description hinted at something related to the word MOO


Step 1 --- Initial Analysis

Starting with a quick metadata and structure inspection:

file MOOOO.jpeg
exiftool MOOOO.jpeg
strings MOOOO.jpeg | less
binwalk MOOOO.jpeg

exiftool and strings revealed an unusual Comment field filled with long repeating MOO, moO, and similar patterns, clearly not human text. The content looked identical to source code in the COW esolang, which uses only variations of the word "moo" for instructions.


Step 2 --- Digging Deeper

Since the JPEG comment looked like COW code, I ran it through an online COW interpreter (any standard COW interpreter or online tool would do). When executed, the output was:

thismaybeapasswordbutwhoreallyknowsimjustmessginitisapassword

That output was a steganography password.

Next, I tried extracting hidden data from the JPEG using steghide:

steghide extract -sf MOOOO.jpeg -p 'thismaybeapasswordbutwhoreallyknowsimjustmessginitisapassword'

The extraction succeeded, producing a ZIP archive named secret.zip.


Step 3 --- Exploit / Solution

After unzipping secret.zip, I found two files: extract.txt and TRYYY.txt.

extract.txt just said:

TRY HARDERRR

which served as a hint to dig deeper.

The second file, TRYYY.txt, contained only spaces and tabs which is a strong indicator of whitespace steganography.

To confirm, I used stegsnow:

sudo apt install -y stegsnow
stegsnow -C TRYYY.txt

That command revealed the final flag:

v1t{D0wn_Th3_St3gN0_R4bb1t_H0l3}

Flag

v1t{D0wn_Th3_St3gN0_R4bb1t_H0l3}

Notes

The challenge combined esoteric language decoding (COW) with classic image steganography (steghide) and whitespace stego (SNOW).