Fc2-ppv-1864525 | !!hot!!

sox audio.wav slice.wav trim 8 2 Open slice.wav in Audacity → “Plot Spectrum” → note the regular on/off bursts.

Using an online Morse decoder (or the morse Python library):

exiftool frames/frame_00123.png | grep -i comment No comment fields. Run zsteg on a few frames (install from Ruby gems or use stegsolve for a quick visual test): fc2-ppv-1864525

import re, sys, json, urllib.parse, requests html = open('page.html').read() m = re.search(r'var\s+videoUrl\s*=\s*"([^"]+)"', html) url = urllib.parse.unquote(m.group(1)) print(url) Result (example):

00000000 66 6c 61 67 7b 46 43 32 5f 50 50 56 5f 31 38 36 |flag4525_fake......| ... sox audio

from morse_talk import decode_morse # Convert the timing into dots/dashes manually or with a script. # The result: .... .-.. .-.. --- ... (example) Decoded text: – again a hint that the flag is embedded elsewhere. 7. Final Flag Extraction The most reliable source turned out to be the trailing bytes after the MP4 container. 7.1 Isolate the trailing segment # Find the start of the trailing data (use `mp4dump` from Bento4) mp4dump fc2_1864525.mp4 | grep -n 'moov' # last occurrence gives offset # Assume last moov ends at byte 124,567,890

But let’s assume the real challenge hides it deeper (e.g., the trailing data is just a decoy). We’ll keep digging to illustrate a full methodology. Even though we already located a flag, extracting the raw streams is useful for later analysis. from morse_talk import decode_morse # Convert the timing

# Get the offset of the final `moov` atom (e.g. 124,567,890) tail -c +124567891 fc2_1864525.mp4 > trailing.bin hexdump -C trailing.bin | head The dump shows plain ASCII: