Objective-C

Well, it has to do with how Apple applications are historically built.

iOS apps are largely written in a language called Objective-C or increasingly Swift.

Right.

And Objective-C is an object-oriented language.

But unlike some languages that compile down to pure stripped machine code, it relies on something called runtime reflection.

Runtime reflection.

I didn't do...

I always, like, worked, I always programmed my way through Objective-C through college, did a lot of PHP and MySQL, stuff like that.

But luckily I, I don't know if I would've still loved it the way I do today.

I don't know if I had to sit through classes and stuff.

In Android, we use Drozer to manipulate intents.

In iOS dynamic analysis, what is the highly specific, slightly ridiculous industry term for intercepting and replacing Objective-C methods at runtime? Is it boozing, lounging, weaseling?

It is certainly not weaseling.

The definitive technique you rely on in iOS is called swizzling.

First, we need a tiny bit of context on the programming language itself.

Traditionally, iOS apps have been built using Objective-C.

Okay.

What's important to know is that Objective-C is a superset of the C programming language.

Why does that matter to us as analysts though?

Because it gives the language this dual nature, It has the high-level organized structure of object-oriented programming, sure.

Method Swizzling.

Yes, Method Swizzling is brilliant.

We want to see how the developer organized the code itself.

Now, in the Apple ecosystem, apps are historically written in Objective-C or Swift.

And because of how these languages operate, particularly Objective-C, a massive amount of structural metadata is actually left behind inside the compiled binary.

Like what kind of metadata?

The names of the classes, the properties, the methods.

Because before we can reverse engineer the logic, we have to profile the target.

And in the Apple ecosystem, that primarily means determining if the app relies on Objective-C, Swift, or a bridged hybrid of the two.

Which is such a crucial first step, because that distinction changes your entire approach to the binary.

How so? Like, why does the language matter that much right out the gate?

Class dump, right.

Yeah,

it parses the Mako file format, specifically targeting the Objective-C runtime segments.

So it extracts the class headers, which basically gives you the definitions of the objects, the properties, and the methods that were compiled into the app.

And Newberg's text is fantastic for this because he treats Swift not just as a tool, but really as an ideology.

Like Swift wasn't just another language Apple threw together to replace Objective-C. It's built from the ground up on three main pillars, which are safety, strictness, and this shockingly elegant internal logic.

It is literally a language actively designed to protect you from your own worst habits.

Okay, let's unpack this.

Right, right.

The idea of primitive scalar types.

Because if you're coming from C or Objective-C, you're used to this weird dichotomy.

You have complex objects on one hand, and then you have primitive raw data on the other.

It was very, very simple, but I felt a great sense of accomplishment.

I'd had to learn Objective C, but that wasn't the hardest part.

No, the hardest part was the API.

Actually, the hardest part was the App Store submission process, but that doesn't serve this narrative.

Which brings us to, well, the kitchen.

If Xcode is the kitchen where developers build everything, the raw ingredients for the longest time were written in this language called Objective-C.

Oh, yeah, Objective-C.

But wait, Objective-C is practically ancient in tech years, right?

It is a wild journey to wrap up.

Right.

We went from writing clean Swift code in Xcode to packaging it in a disguised zip sandbox to forcefully tearing down those walls with a kernel exploit.

The tension between securing a system and human curiosity to break it is just relentless.

So there, there isn't that many protections there, but with most, with most things, it's like, it's just social engineering and that's the main way in.

If you want good security tools for like a little bit of extra knowledge, Patrick Wordles and Objective-C's tools are really where it's at.

I remember one of his tools was something that would take a picture the minute you open up the screen.

So you can see if someone's trying to get in or sneak into your Mac and things like that.