What's hiding inside this mystery audio file?

1

I have an unusual problem, of which I am struggling to find any answer.

After cleaning out my Windows installation, I found an m4a song file set as hidden in my documents (The Mother We Share by CHVRCHES). It was last modified in 2016, and I do vaguely remember putting it there.

The song will play perfectly fine, up until 2:20 - when it crashes the audio player.

Comparing this file to the original I have in my music library; the files are different. The compare plugin in Notepad++ shows lots of lines in the middle of the file are altered, and the mystery hidden version is shorter than the original.

Notepad++ Compare screenshot

I believe something is hidden inside The Mother We Share.m4v - but I've tried everything I can think of to extract the data and I can't find anything. I checked my google history from that date but no clues.

I am cautious about posting the mystery file online, just in case I hid something sensitive inside the file. I have posted about half of the modified lines below (from lines 14183 to 14625) - maybe someone can help me uncover the truth about this unusual file?

Link to pastebin dump

XDGFX

Posted 2019-05-19T14:10:08.020

Reputation: 61

Answers

1

Well, did you hide something in it?

If it hasn't been touched in years then it probably wouldn't be too far off to assume the file just got corrupted during some transfer or update or something.

Maybe try playing the file with a different audio player and see what happens. I don't think you can really hide something in a file like that.

CatLadyish

Posted 2019-05-19T14:10:08.020

Reputation: 21

I feel like yes, I did hide something. I just can't remember what or how. I'm confident it's not just corrupted; why would I have saved it in my Documents as a hidden file? Good idea, I'll do that now – XDGFX – 2019-05-19T15:24:08.863

Update: Same result in Windows Media Player as VLC. Opening in Audacity just shows the file cutting off at 2:20 – XDGFX – 2019-05-19T15:30:30.390

@XDGFX honestly not sure.. I feel like hiding anything in the code for the file would just corrupt it and destroy any message – CatLadyish – 2019-05-19T15:49:03.680

Well to be fair it did corrupt the original file! – XDGFX – 2019-05-19T16:05:42.497

Steganography (hiding data) inside media files is possible. That said, it can be difficult to do in an undetectable manner. – Anaksunaman – 2019-05-19T17:49:53.090

@Anaksunaman I know it's possible, and while I honestly don't know a LOT about it, i guess it feels weird that you could go in and modify an encrypted file's text and save it and have the file at all work and keep the hidden message in tact. – CatLadyish – 2019-05-19T18:15:33.433

Asked: 2019-05-19T14:10:08.020

Viewed: 32 times

Active: 2019-05-19T15:17:05.243