Rating:

Players download a PCAP. There's a lot of noise from random HTTPS traffic, so they should filter by SMB and see this WAV file transfer.

![Image](https://cryptocat.me/blog/ctf/2024/intigriti/forensics/ctf_mind_tricks/images/smb-filter.png)

Return to the start of the request, then follow the TCP stream.

![Image](https://cryptocat.me/blog/ctf/2024/intigriti/forensics/ctf_mind_tricks/images/follow-tcp-stream.png)

You can convert the ASCII to raw and save this as a .MP4 file.

![Image](https://cryptocat.me/blog/ctf/2024/intigriti/forensics/ctf_mind_tricks/images/ascii-to-raw.png)

Alternatively, just go to `File > Export Objects > SMB`.

![Image](https://cryptocat.me/blog/ctf/2024/intigriti/forensics/ctf_mind_tricks/images/export-smb-objects.png)

You'll find an AI song I generated with [suno](https://suno.com).

If you closed the PCAP here though, you missed a step! If you look through the ports (I recommend filtering out HTTP(S) with `!(tcp.port == 80 || tcp.port == 443)`), you'll a suspicious one; `1337`.

![Image](https://cryptocat.me/blog/ctf/2024/intigriti/forensics/ctf_mind_tricks/images/port-1337-chat.png)

```
I need to send you a message but I can't remember what frequency you said?
It was 18-21kHz.
Sending the song via SMB now.
Oh, how interesting.. Thanks!
```

So, there's something hidden in some frequency of the audio ? We can isolate these things with `sonic-visualizer` or `Audacity`. I went with the latter.

![Image](https://cryptocat.me/blog/ctf/2024/intigriti/forensics/ctf_mind_tricks/images/audacity-waveform.png)

Viewing the spectrogram doesn't reveal anything.

![Image](https://cryptocat.me/blog/ctf/2024/intigriti/forensics/ctf_mind_tricks/images/default-spectrogram.png)

We need to configure the range between `18000hz` to `21000hz`.

![Image](https://cryptocat.me/blog/ctf/2024/intigriti/forensics/ctf_mind_tricks/images/high-frequency-spectrogram.png)

Flag: `INTIGRITI{hidden_in_music_1337}`

Original writeup (https://cryptocat.me/blog/ctf/2024/intigriti/forensics/ctf_mind_tricks/).