Newport Blake CTF 2023
Do You Hear That [241 pts]
Challenge Description:
I’m not sure why, but when I look at this image I can hear some sort of faint sound. Do you hear it too?
The challenge description suggests there may be an audio file stored in this PNG file.
Let’s run binwalk on the program. It shows something called a “TIFF” image file?
Checking out the bytes around that offset shows two very suspicious strings, “RIFF” (at 0x8A24) and “WAVE”. A quick google search informs us that this is a .wav file.
Simply extracting the bytes with a hex editor like HxD gives us our .wav file. However, if you take a listen, the audio file seems to be utter nonsense.
A common strategy with audio forensics, though, is to use a program like Audacity to check the spectrogram of the audio file and see if there’s a hidden message. And indeed, a quick check gives us our flag!
nbctf{y0u_h4v3_s0m3_g00d_34rs}
