Fc2-ppv-1864525 -

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.

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): fc2-ppv-1864525

# 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: But let’s assume the real challenge hides it deeper (e

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): import re, sys, json, urllib

Use exiftool on a few frames to see if any hidden data was appended:

Extract the trailing bytes: