---
description: Audio steganography - spectrogram
---

# Frequency

## Description

I can hear flag...I think....or I am insane?

Attachment: `challenge.wav`



## Solution

Listening to the audio file will give us some weird "alien" sound. There is no useful information from the audio. Therefore, we can try analyzing the audio using tools like [Audacity ](https://www.audacityteam.org/)or [Sonic Visualizer](https://www.sonicvisualiser.org/download.html).

<figure><img src="https://3139068166-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F5otAmBnHXiDB0QXOOAMF%2Fuploads%2FXzc8vloHvUFGOswCZry1%2Fimage.png?alt=media&#x26;token=d02d661a-bc72-4d34-8e36-5e702835194c" alt=""><figcaption></figcaption></figure>

Waveform of the audio does not give us any useful information. In audio steganography, most of the time people hide information in the spectrogram.&#x20;

<figure><img src="https://3139068166-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F5otAmBnHXiDB0QXOOAMF%2Fuploads%2FNgjRhVmJDoZeQZ5pQPJg%2Fimage.png?alt=media&#x26;token=75d1ffcd-a96c-4e04-8e40-faf06d169314" alt=""><figcaption></figcaption></figure>

Therefore, we can try to view the audio in spectrogram. Spectrogram is a visual representation of the frequency of a signal and the amplitude, which is useful for hiding information.

<figure><img src="https://3139068166-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F5otAmBnHXiDB0QXOOAMF%2Fuploads%2F4AjOZBqQEj3OjBAdk3Yi%2Fimage.png?alt=media&#x26;token=27ab2393-eb05-4b50-849f-c7922c0fcdca" alt=""><figcaption></figcaption></figure>

This is the spectrogram of the audio, which shows the flag.



## Flag

`GCTF2023{this_fl4g_sounds_weirddddddd}`
