How to find and play videos downloaded by Lynda.com Android or Windows app

Question

There is an App which features downloading their videos for offline viewing via their Android and Windows app. I was wondering where does this app saves these videos and if they are encrypted, how to decrypt and play them?

I am a programmer but I know nothing about Android/windows app development, here is what I have been able to hack so far:

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On Android

It seems like it saves videos at

/storage/emulated/0/Android/data/com..android.root/files/videos//encrypted/

These files have no extension, I copied them to my laptop and tried giving different popular media extensions, nothing worked so far in neither of WMP, VLC & Quicktime Player.

I tried to identify file type using TrID (as specified in this link and this utility suggests it is an mp3 file (while it should be a video), I changed the extension to mp3, it did not worked either.

I tried opening the file in ISO buster and several other apps. Finally while trying different things, on android system itself when I choose the option to compute checks, it display some MD5 and SHA-1 values. I am not much familiar with these terms but figured out, these files seems to be encrypted.

If I try to directly open this file on Android, System starts generating Hex Dump and then file explorer crashes.

Now if these files are really the video files and are encrypted, is there a way I can decrypt them and play directly in a video player?

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On windows store App in my laptop's Windows 8.1

I found App files are stored at:

C:\Program Files\WindowsApps\.com..com_1.5.0.2_neutral_split.scale-140_

C:\Program Files\WindowsApps\.com..com_1.5.0.2_x64__

C:\Program Files\WindowsApps\.com..com_2015.924.1324.2728_neutral_~_

I was able to figure out how to assign privileges to currently logged in User and gain the access to reach at these paths but couldn't make any further progress to find encrypted or non-encrypted video files in these folders at all.

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I understand that if I really just want to download the video files there is much better and easier way - directly log in to their website and use any video grabber application or extension, it's as easy as that, which does works.

But my intention here is not to download videos but rather I am just curious to do ethical hacking for learning and exploring things. Just want to understand whether it is even possible to decrypt, find appropriate extension and play them directly without the app or not. And where does both Android and Windows Apps are actually storing these videos on my own device which I am unable to access/play without App.. huh well done app developers!

Any help or pointers appreciated.

Answer 1

Alright, so the above listed solutions worked for a while but Lynda was smart enough to begin encrypting the downloaded videos. And hence just finding the downloaded content is not good enough anymore.

I could not find a way to decrypt the videos downloaded by the Windows Store app but someone did a great job in decrypting the videos downloaded by the Desktop app (yes, it is different), which is not as popular as the store app. You can download the desktop version of this app from here.

Find encrypted downloaded vdos here:

C:\Users\\AppData\Local\lynda.com\Lynda.com Desktop App\offline\ldc_dl_courses

and decrypt them using this tool.