Did you watch the video for flashing frames, QR codes, or Morse code? 3. Deep Dive & Exploitation

Did you find the flag by running strings 3137.mp4 | grep "CTF{" ? 4. Final Flag Flag: FLAGexample_flag_123

If the video looked normal, did you check the audio track? Mention if you used Audacity or Sonic Visualizer to look at the Spectrogram for hidden text.

This is the core of your write-up. Explain the "Aha!" moment:

Use file 3137.mp4 to confirm it is actually an MP4 and not a renamed archive or polyglot file.

If you found something in a single frame, explain how you extracted it using ffmpeg -i 3137.mp4 -vf "select=eq(n\,3137)" -vframes 1 out.png .

List your toolkit, such as ExifTool , FFmpeg , StegSolve , Sonic Visualizer , or Strings . 2. Initial Analysis Describe your first steps after receiving the file: