With his dying breath, Prof. Ter Stegen hands us an image and a recording. He tells us that the image is least significant, but is a numerical key to the recording and the recording hides the answer. It may seem as though it's all for nothing, but trust me it's not.
We open the Image using Stegsolve.jar and we get the numerical key in
RGB Pane 0
So using this code we can use steghide to get hidden data from the wav file with
steghide --extract -cf morse.wav -p 42845193
We get a flag.txt file which is empty. Opening it in hex editor we see
00000000: 2020 2009 0920 2020 0909 0d0a 090d 0a20 .. .......
We find out that the ascii for these hex codes are
20 - Space
So googling "
file with only tab and space ctf" we come across this writeup written by John Hammond. Following the steps given and replacing
\t with 1 and
' ' with 0, we get the flag.