Challenge Information

  • Category: Steganography
  • Description:

Max was listening to her favorite song on loop to keep Vecna out of her mind. However, we intercepted her walkman and noticed a strange, high-pitched anomaly in the background of the track. What is Vecna’s message?

Files Provided

Analysis

The challenge description hints at a “high-pitched anomaly” in the background of a WAV file. This is a common indicator for audio spectrogram steganography, where data is hidden visually in the frequency domain.

1. Metadata Inspection

First, we check the audio properties:

exiftool cursed_tape.wav

ExifTool Version Number         : 13.25
File Name                       : cursed_tape.wav
Directory                       : steganography/The Max Mayfield Tape
File Size                       : 2.7 MB
File Modification Date/Time     : 2026:03:26 08:11:50+07:00
File Access Date/Time           : 2026:03:27 22:24:31+07:00
File Inode Change Date/Time     : 2026:03:26 10:10:55+07:00
File Permissions                : -rwxrwxrwx
File Type                       : WAV
File Type Extension             : wav
MIME Type                       : audio/x-wav
Encoding                        : Microsoft PCM
Num Channels                    : 1
Sample Rate                     : 44100
Avg Bytes Per Sec               : 88200
Bits Per Sample                 : 16
Duration                        : 0:00:31

The file is a standard 16-bit Mono PCM WAV file at 44.1kHz.

2. Spectrogram Generation

To visualize the frequencies, we can use ffmpeg to generate a high-resolution linear spectrogram:

ffmpeg -i cursed_tape.wav -lavfi showspectrumpic=s=2048x1024:legend=0:scale=lin spectrogram.png

Solution

Upon inspecting the generated spectrogram.png, the flag is clearly visible in the mid-to-high frequency range, superimposed over the audio signal.

spectogram

Flag

CTF{V3cn4_1s_L1st3n1ng}