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):
sox audio.wav slice.wav trim 8 2 Open slice.wav in Audacity → “Plot Spectrum” → note the regular on/off bursts.
dd if=fc2_1864525.mp4 of=payload.bin bs=1 skip=124567890 strings payload.bin | grep -i flag # => flagFC2_PPV_1864525_fake Flag: fc2-ppv-1864525
Using an online Morse decoder (or the morse Python library):
00000000 66 6c 61 67 7b 46 43 32 5f 50 50 56 5f 31 38 36 |flagFC2_PPV_186......| ... exiftool frames/frame_00123
# 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:
Extract the trailing bytes:
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