Hello everybody
The issue of Audio Units within iOS apps not working is very known by now. As I've seen in other posts, there are several folks interested in this topic, coming back every now and then asking for news (VivaLaBamm, I'm looking at you). To them I wanna say, you can do more than you are doin right now! Without a doubt, together we can make it happen.
It is clear you don't need to know about the technical stuff in order to contribute. If you really don't have a clue, contact to someone that shed some light on the subject, and may be willing to help us, either IRL or thru internet. If you can do a little more than the average PC user, just like me, search for information and share it.
Having said that, I'll tell you about what can be the starting point. A little story: I was interested in trying out a pricey EQ plugin for Cubasis, and proceeded to download the cracked .ipa file. The app was installed successfully using Filza, but when I finally opened it, app never finished loading. It turned out it was just a container for the plugin, which wasn’t obviously decrypted properly. So I spend around half an hour searching for a solution somewhere in the internet, there was little discussion about it other than posts in this forum.
Then I realized I had to take a step back and understand how iOS apps and their corresponding Audio Units work.
After extracting files of the cracked .ipa I observed AUv3 was inside a folder named Plugins, and with an extension .appex, and inside that file there was another _CodeSignature folder, another binary and other identical files as the main app. It just seemed to be clear the plugin was also signed, but proof was needed indeed.
Apple Developer documentation (https://developer.ap...tyPG/index.html) teaches us that AUs are just a kind of something called App Extensions: code that “lets you extend custom functionality and content beyond your app”. An app extension is also a “separate binary that runs independent of the app used to deliver it”. The link provided explains in a detailed way how these plugins behave and how they interact with the host app, I recommend you to check it out.
Medium.com, an excellent technical guide for programming and stuff, has a great summary about it (https://everisus.med...le-f340fe074efd).
Now we can see, looking up not “how to crack iOS apps with Audio Units” but “how to crack iOS apps with app extensions” is the way to do it. And that’s how I came across with this jewel:
https://web.archive....s-applications/
This is a comprehensive guide for security researchers on how to resign apps that contain not only frameworks but also app extensions and even Watchkit apps.
In the following days I’m replicating the guide’s examples and doing a little bit of testing, I’m hoping you to do the same thing.
Thank you for reading til here, and hope to read from you soon!
My very best
Victor M.