Fc2-ppv-1864525 Direct

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

Use exiftool on a few frames to see if any hidden data was appended: fc2-ppv-1864525

zsteg -a frames/frame_00123.png No obvious LSB payload. The audio track is often used for hidden data. 6.1 Convert audio to WAV ffmpeg -i audio.aac audio.wav 6.2 Spectrogram inspection sonogram -i audio.wav -o spectrogram.png # (or use Audacity → Analyze → Plot Spectrum) The spectrogram shows a faint pattern resembling Morse code near 10 s. 6.3 Extract Morse Export the 8–10 s slice: Using an online Morse decoder (or the morse

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): .-.. .-.. --- ...

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